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I’m known for being a bit of a purist with my retro PC builds. Sure I’ll make exceptions at times, use a CF or SDD HDD here and there (out of sight out of mind right?), use a CD-ROM or DVD drive in a system that probably wouldn’t of had one back in the day or even throw a floppy emulator into some problematic floppy only systems but generally I like to stick to period correct builds with hardware more or less from the time period. With this build though I’m going to step away from that a little bit and build what I call DOSzilla, A super powerful yet highly compatible DOS based gaming PC with key parts more or less outside of the era that DOS was a prevalent or even moderately used as a operating system in the home.

If your looking for a fast but more era correct DOS PC check out my article on my fast Pentium MMX DOS PC.

One of the pickiest components when building a DOS PC is the sound card. DOS always works best with a 16-bit ISA sound card. There are PCI sound cards like those based on the Aureal Vortex chip that do a pretty good job of working under DOS, especially with later games but I wanted to go for as high of a compatibility and ease of use as I could and this meant I needed a motherboard with a 16-bit ISA slot. This basically limits us to either a Pentium III motherboard that supports up to a 1.4ghz Tualatin CPU or a AMD Athlon socket A Thunderbird motherboard that supports up to a 1.4ghz AMD Thunderbird CPU. There are motherboards that support faster CPU’s as well as having a 16-bit ISA slot but they tend to be for industrial applications and are expensive and hard to find so for this project I wanted to keep costs low and components easily attainable.

If your wondering about performance between the Intel 1.4ghz Tualatin and the AMD 1.4ghz Thunderbird they are relatively similar but it depends on the application and game. Here is an example of some benchmarks I performed using this motherboard and a separate PIII board though note different motherboards may give varying results.

Motherboard – Tyan S2390

Either motherboard choice is fine but I went with a AMD board just for something a little different. The motherboard I chose was the Tyan S2390, a socket A board which uses the VIA KT-133 chipset.

This is a pretty good performing motherboard that met my immediate needs. It supported a Thunderbird 1.4ghz CPU (though that manual states it can only accept up to a 1ghz CPU) had a x4 AGP slot, BIOS options to disable internal cache and finally had one all important 16-bit ISA slot.

For my operating system I’m just using my old fallback of DOS 6.22 but if your feeling adventurous you could try DOS 7.1 which some people have managed to isolate from Windows 9x and make into its own standalone OS. This MAY induce a few compatibility issues with a rare few picky games but on the upside you can use much larger hard drive sizes and partitions.

CPU – AMD 1.4ghz Thunderbird

So first we need to talk about my choice of CPU, the AMD 1.4ghz Thunderbird.

Image courtesy of Wikipedia

Released in 2001 the 1.4ghz model is the final and fastest CPU in AMD’s Thunderbird core chips. Things to note is this CPU can be a little hard to find as well as it runs a little hot so make sure you use a decent heatsink / fan combo. This CPU is also the fastest CPU my motherboard will accept even though official documentation says it will only support CPU’s of up to 1ghz this is probably because the motherboard came out roughly a year before the 1.4ghz Thunderbird was a thing.

I also like this motherboard / CPU combo because although 2001 is well after the death of DOS as a mainstream home OS or platform for gaming it’s not to far out of the era to count as ridiculous overkill as bigger DOS titles were still being released in 97 and probably 98 only three or so years earlier. All the extra horsepower does have one big advantage and that’s running many of these later DOS titles much smoother then PC’s of their time could especially in higher resolutions that games such as Quake offered.

One major downside of such speed though is greater incompatibility with games due to mostly speed issues. This results in some titles running far to quickly or sometimes more subtle issues such as a game appearing to run fine but timed events hidden in the background running to quickly. This can be especially prevalent with older titles where a CPU was expected to be running at a mere 33mhz or 66mhz let alone 1.4ghz.

This issue can be mitigated somewhat by the BIOS option to disable internal cache on the CPU. My testing with programs like Topbench has shown when the internal cache is disabled in BIOS on the 1.4ghz Thunderbird it performs similar to a 33-50mhz 486DX.


For RAM I’m using one stick of 512MB PC133 SDRAM. This is actually massive overkill and may actually adversely effect compatibility with a few rare titles. I’m just using it for the sake of trying it but if you want to play things safer a 128mb stick or even a 64mb stick would be best. If though your planning on duel booting Win 9x or running Windows as your main OS and using DOS mode stick with 512mb.

HDD – Maxtor ATA133 HDD & Promise ATA100 PCI IDE controller

The Tyan S2390 only has ATA66 on the built in IDE controller which although adequate I wanted to go a bit faster. For a hard drive I could easily have thrown in a SATA adapter and a SSD or even SD card as a hard drive but I wanted to just go with something I already had laying around so I opted for a 40GB Maxtor ATA133 hard drive with a PCI ATA100 IDE card I had on hand. using this card I do lose a bit of performance from the I could of gotten out of the hard drive as well as wasting a lot of hard drive space as my setup can only see 2GB of the hard drive.

If you have one lying around or want to spend the few extra dollars you shouldn’t have any issues with throwing in a PCI SATA adapter card and a SATA hard drive or even SSD.

Video – Diamond Stealth S540 Savage 4 Pro

For a video card I wanted to go with something very capable and fast but also a card that gave the highest compatibility with older DOS titles. For this I went with the AGP S3 Savage 4 pro chip in the form of the 32mb Diamond Stealth III S540

S3 cards from the mid 90’s such as the S3 Trio and Virge were known for their excellent and highly compatible 2D core and the Savage 4 chip is no different. Also like their earlier cards the Savage 4  wasn’t really known as being a speed demon and was generally outclassed by cards from Nvidia and 3DFX such as the TNT2 and Voodoo 3 but in our DOS build the Savage 4 based S540 is more then powerful enough as well as delivering that excellent 2D image and compatibility. The card I’m using here is the AGP x4 pro chip but if you want a card a little faster look for the Savage 4 Xtreme.

Sound – Creative AWE64

Lastly we have the sound card. Obviously we I wanted to go with a 16-bit ISA card for a large degree of hassle free DOS compatibility. The card I ended up going with largely for for the reason of having one in easy reach was the Creative AWE64.

Keep in mind there are many acceptable sound cards one can use for this project. I went with the AWE64 for its good compatibility and sound quality. In DOS the AWE64 acts just like an AWE32 and many later DOS games directly support it in setup options, otherwise it usually can emulate a SB pretty well. It also can do its own MIDI which although usually not as good as an external module still sounds acceptable with many later games. It does have its drawbacks though such as a lack of a real OPL FM chip but since this PC is heavily geared to later games that would take more advantage of MIDI or a CD soundtrack I felt it was a still a great choice. This model also lacks a wavetable header so no MIDI daughterboard add-ons. Again though, if you have a different preference many other ISA cards should work just fine such as an AWQE32 with a MIDI daughterboard of your choosing or a Sound Blaster 16 or clone.

Games, Overall Performance and Conclusion

Now to take a look at how this PC performed for me once all put together. First a look at some Benchmarks with my more period correct Pentium based fast DOS PC

RED = DOSzilla

GREEN = 233mhz Pentium DOS PC, 2mb L2 cache, 132MB PC133 SDRAM, Virge/GX

As expected DOSzilla stomps the Pentium 1 PC. For some reason my benchmark for Wolf3d wouldn’t even run on the Pentium rig but this could be due to anything. Some benchmarks turn out surprisingly close though like DOOM. If my terrible math skills are correct it’s only about 30% slower on the Pentium MMX PC.

As for games I did test a number of them including a few older titles. The games I tested and the results are

DOOM – no issues

Quake – no issues

Tex Murphy, Under a Killing Moon – no issues

Duke Nukem 3D – no issues

Decent 2 – ran to fast, corrected by disabling CPU cache in BIOS

Commander Keen 4 – no issues

Star Wars Dark Forces – no issues

Wolfenstein 3D – no issues

Double Dragon – no issues

Major Stryker – failed to install (this is due to a installer bug if your hard drive is to big, even happens on a 386 if the HDD is > 1GB)

Even though I didn’t play any of these games on DOSzilla extensively I was surprised by the initial excellent compatibility. most of the late era games ran just fine with pretty much zero issues in gameplay, graphics or setting up the sound in the install. Everything just worked for the most part. Decent 2 did run to fast but restarting and turning off internal CPU cache in the BIOS options corrected this. Major Stryker failed to install but this was due to the HDD being to large which happens on any PC regardless of the CPU if you use a HDD > 1GB. Of course this is a very small sampling of DOS games from a library of thousands so there is bound to be compatibility issues especially in older titles but overall I was impressed by the initial trials.

As for Quake and some of its ridiculously taxing resolution options for the time DOSzilla was able to run the game in 1280 x 1024 though gameplay was not optimal and quite choppy. It was technically playable but not a great experience. I suspect a fast video card could help in this department. The game did run at a perfectly acceptable framerate at 1024 x 768 though.

In conclusion I think DOSzilla makes a fine DOS PC. I still prefer a more traditional retro PC using a bit more period correct parts. I feel a slower machine does offer better all around compatibility and just feels a bit more special. That said I was impressed with DOSzillas compatibility, at least with later DOS titles likely due to the 16-bit ISA sound card and S3 video. The ability to actually play games like Quake in higher resolutions was nice but as I said I suspect more and more issues with CPU speed would crop up as you played more and more older titles. All in all if you have the parts and are looking for a DOS rig with an emphasis on playing late 90’s games go ahead and build your own DOSzilla.



I’ve said it before but for those that did not grow up using a command line interface operating system MS-DOS can come off as being quite intimidating. For me I grew up on the Amiga and C64 and my first PC was running Win95 so when I first became interested in DOS I was quite intimidated. Sure I played on PC’s that friends had prior that ran DOS but it almost seemed like computer sorcery as a kid to remember all those commands and navigate the maze of text commands and directories. The reality of the fact though is DOS is very easy to learn and game on once you get the basics. The scope of this article though is taking those first steps, as in installing and doing your initial optimization of the memory since that seems to be the aspect that trouble many new users of the OS. I’m not going to get to into drivers or hardware to much, with the exception of hard drives since they form an important aspect of installing the OS. This guide is also specifically for MS-DOS 6.22 since that is the OS that a majority of DOS users are going to be running on an older machine. There are also a number of DOS alternatives like PC-DOS and FreeDOS that I know about and have varying degrees of compatibility. I’m completely aware of these alternatives and am also aware that some of them work very well and have some advantages. If your interested in them do a Google search but this article will focus on installing and optimizing MS-DOS for a highly compatible DOS experience. I’m also not going to go into any super exotic hardware options I’m just going to keep it simple with the hardware I feel a large majority of people referring to this guide will and or should be using.

First off for DOS 6.22 I would defiantly recommend a 386 based PC or above. A 386 to a Pentium 1 233mhz would be the ideal range of computers to run it on but it can be installed without issues on faster computers though games and applications may have speed issues with the CPU and hardware issues may arise depending. For anything slower then a 386 like a 286 or 8088 I would recommend dos 3 for those CPU’s as from what Ive read DOS 6 will run on a 286 and lower but I believe it uses some aspects of 386 and above CPU’s so you won’t be getting its full potential and there may be some conflicts that occur (just speculation on my part but I’m assuming its possible).

So first off were going to take a look at our hard drive and connection options since this is where were going to be installing the OS. Also I’m going to assume you have a 1.44mb floppy drive installed since this is the only format I’ve ever seen DOS 6.22 come on. I’m pretty sure there’s 1.2mb floppy and 720k floppy versions out there but I’m going to assume that the vast majority here will be installing from a 1.44mb floppy. From what I know there was never a CD release of the OS but I have heard of a way some people have found of burning and setting it up on a CD in a manner that it can boot and install from it. I’ve never gotten this method to work nor have actually seen it work.


If you have the most common 1.44mb floppy version you should have 3 disks minimum to install. There may be a forth disk with optional extras and tools. If there is I’ve never utilized it.

So now that we have our OS and disks ready we need to choose and setup our hard drive. There are a variety of hard drive types to choose from so I’m going to cover the most common.

MFM drive


If your hard drive your planning to use is kinda big and has the same connector as your 5 1/4 floppy drive (if you’ve ever used one) its a MFM drive. These are old and generally very small in data capacity size, 10 to a few hundred megabytes. These are how very early PC’s interfaced with hard drives. They are comparatively slow, small in space available and unreliable. Unless its the only thing you have around I would not recommend using one. You will almost defiantly need a 8 or 16 bit ISA controller card that can specifically handle these types of drives. If the computer your using has one of these pre installed its probably vintage enough that your probability better off installing DOS 3 anyways.

SATA drive


SATA is the newest type of hard drive connection that really starting appearing in mass in the mid 2000’s. Successor to IDE it is fast and the cables are nice and small. Unfortunately what I can find on the subject is a little unclear. If your using a new motherboard with SATA ports or have a older (say socket 7) motherboard with PCI slots you can get a PCI SATA card but from what I can find DOS may or may not detect and install. Those that have gotten it to work report that like SCSI that I’ll talk about in a moment it does overcome the BIOS hard drive size limitation. I found that certain CD-ROM drivers will work in DOS to detect and use SATA CD based drives but information on the hard drive aspect seems pretty sketchy. On these grounds I would just avoid using SATA. Its extra work, IDE or SCSI drives are far cheaper and although it probably can be made to work DOS isn’t going to be able to utilize that 500GB drive space anyways. This also obviously not an option if your working with most 486 era motherboards and earlier since they lack PCI slots.

Compact Flash


The next option would be to use a compact flash card and a CFtoIDE device. CF is basically IDE so It won’t give you to many issues. You can find the adapters for a few dollars on eBay and a 512mb CF card for a few more. The upsides of these cards is they are completely silent, run cooler, use very little power and are very fast since there are no moving parts. Its basically a small solid state hard drive. One issue that you may run into is that not all IDE connectors on motherboards or IDE controller cards and CF cards get along. I had an older 486 that would not detect or boot from a CF card and I had to buy a separate IDE controller that ate one of my ISA slots to get it to work. Some cards require being initialized as hard drive mode as well. I do know people that use them in their every day heavy use vintage machines under DOS and have recorded very little to no issues but they do have a finite read/write ability. Personally I stick to more tried and true conventional drives in my systems but I will use CF drives in lesser used or special purpose systems. There are also “Micro drives” which are CF sized conventional hard drives. This Wikipedia article directly compares them to CF drives here.


now will go over the two most likely drives you’ll be using and there pros and cons. First is IDE or “Integrated Drive Electronics” or “Intelligent Drive Electronics”. This is by far the most common way hard drives were interfaced with household PC’s throughout the 90’s and into the 2000’s. Most motherboards starting in the Pentium era of the 90’s had two IDE controllers integrated into the board and a large number of 486 and even some 386 boards features one IDE interface. SCSI or “Small Computer System Interface” rarely had interfaces on the motherboard of PC’s and usually required a controller card. SCSI was largely favored by Macintosh and Amiga computers.

so for the pros and cons



  • easily and cheaply available
  • most motherboards already have interfaces built in saving you a expansion card slot
  • less hassle setting up


  • considered slower and less reliable then SCSI
  • limited to two IDE devices per cable, one device acts as a slave and the other a master
  • usually a Bios imposed partition size limit of 504MB under DOS without extra modifications or adjustments
  • older drives/interface cards may require a older style IDE cable (connector is exactly the same but older style cable has larger ribbons in it)



  • considered to be faster, has own controller thus taking burden off CPU and freeing CPU power.
  • generally considered more reliable then IDE (usually the choice for 24/7 running server machines)
  • 7 to 15 devices depending on a single controller
  • not hampered by BIOS size limits in older machines. easier to have up to 2GB drive partitions in DOS


  • generally harder to come by and more expensive then IDE
  • can be harder to set up and be booted from (last drive or connector on chain requires a terminator)
  • in general drives may be louder then IDE drives
  • several revisions and version of the SCSI interface that may be confusing
  • will most likely require an SCSI controller add-on card taking up an expansion slot

So in short SCSI is usually the way to go if you have a little more money and time to spend and the patience to set things up properly where IDE is good for a cheap drive that usually “just works” with minimum surprises. Not that SCSI is generally hard to get up and running but depending on the machine, controller card and drive you may have to spend a little more time setting it up. Also keep in mind that although SCSI is considered in general a little faster and more reliable then IDE a good quality IDE drive is going to be faster and more reliable then a low quality SCSI drive.

IDE to SCSI adaptor

I wanted to briefly go over one other option that for a price gets you the best of both worlds, this is the IDE to SCSI adapter. Basically what these little adapters do is allow IDE devices to be used by an SCSI controller. so with one of these you could get a cheap easy to find IDE hard drive and connect it to your SCSI controller and benefit from the SCSI controller handling things and not the CPU. One popular option is to pair a IDE to SCSI adapter with a compact flash card and adapter creating an extremely fast solid state drive option. Unfortunately unlike the IDE to CF adapters the IDE to SCSI cards are rather expensive. A few years ago I picked one up for about $45 and that seemed to be the average price but recently (2013) they seem to be going for well over $100 on average.


Above are three drives. They all look very similar but they are two SCSI drives of the 50 pin and 68 pin variety and a IDE drive. Ironically the IDE drive is the Apple branded drive. Its ironic because Apple tended to use SCSI drives in most of its computers.


Here are those same drives with Interfaces up so we can see the difference. They all use the same type of 4 pin molex power connector. The IDE drive on the bottom has a jumper to select “slave”, “master” or “cable select”. I never use cable select. Generally you want to have your hard drive set as master and your CD-rom drive set as slave. You can see the drive above that is the 50 pin SCSI. The 50 Pin standard is the older style connector for SCSI you will find on the older drives as well as most SCSI CD drives. Its slightly larger then the IDE connector. Also notice no jumper next it since slave/master settings are not necessary on SCSI. Finally we have the 68 pin SCSI which is a newer and faster standard. The connector is very different looking from IDE or 50 pin and much more compact. 68 pin drives can be connected to a 50 pin controller card and cable via a 68 pin to 50 pin adapter but this will cut its speed.

If you go with an IDE hard drive there’s a almost guaranteed chance that you already have two interfaces on your motherboard if its socket 7 or later and a fair chance you have at least one if its a 486 board. It should look like this though on mostly older boards if it is present it may not have the plastic guide around it and just be pins.


If your board does not have a built in connector or if your using SCSI your going to need to add a controller card. The faster the slot the better with PCI being the best followed by EISA and VLB and finally ISA. Here are two typical examples of 16 bit ISA controller cards.


You generally do not need to do anything but insert them in the slot and hook up the drives. You may need to set or adjust some jumpers but other then that they should load their own BIOS’s on boot up. If your running SCSI remember that that last device on the chain needs to have its jumper set to terminate (check your drives manual, most can still be found online), if there is no device on the final connection on your SCSI cable you may need a terminator. The terminator pictured below is actually for an external SCSI chain but the internal ones are similar.


Also if you’ve gone the IDE route and are having trouble getting the IDE drive detected try switching the Slave/Master setting if you have a second drive or CD drive present as some drives and setups are just oddly picky about that. Also try swapping between the two styles of IDE cables if you have them. Especially if its an older motherboard.


The newer style cable is on the left. As you can see there are much more ribbons then the older style cable on the right. Keep in mind that you need to be using the newer style 80 pin ribbon (on left) if you want to take advantage of higher speeds if you are using a ATA-33 through ATA-133 drive and controller otherwise it will still work but you will be limited in speed.

You may also come across some oddball types or full  height drives. As far as I know these drives are basically functionally identical but different sized.


The IDE “Bigfoot” drives were popular with Compaq in the earlier Pentium days. There very large but thin and are in general slow. you would probably have a hard time fitting these in a standard tower setup and I’ve only come across them in OEM cases. The SCSI is a full height drive which is an older style and is taller then a more common 3.5″ drive.


Newer SCSI drives may use a combined connector that combines the power and data cable. These are usually pretty fast drives (15,000 RPM’s) that come from servers and are pretty overkill for a vintage system. If you do want to use one though you’ll need a adapter that changes the single connector to a 68pin SCSI and molex connector.


Okay now hopefully BIOS is detecting your hard drive on boot so we can get to the business of installing DOS. If your CMOS battery is dead or you also just installed a 1.44mb floppy drive you may need to enter the BIOS and setup the drive. Its also useful to know how to access the BIOS to set boot order in case you want to use a 3rd party CD disk partitioner. Generally you can access the BIOS during boot my pressing Delete or F2. Usually your boot screen will tell you this information in the lower section of the screen. BIOS screens and options vary wildly between systems so mine may not be representative of yours but most of them are similar in key respects.


Here is my initial BIOS screen. Selecting BIOS features setup lets me change boot order in case I want to boot from a CD drive before the hard drive. Under Standard CMOS settings I can set my 1.44mb floppy drive as drive A:.

You can also use a 3rd party disk partitioner at this point if you want to reformat your hard drive and set up separate partitions on a single disc if you want. The MS-DOS floppies will reformat the hard drive for you and will give you that option booting to them but a 3rd party partitioner may offer more options. I use Super Fdisk myself available here.

If formatting from the DOS disks your fine but if your using a third party formatting program make sure you format the drive to FAT 16 since that what DOS can “see”. DOS 7 can use FAT 32 but as were are assuming DOS 6.22 is being installed that’s irrelevant. Keep in Mind most old BIOS’s can only detect up to 504mb of hard drive space for DOS on an IDE drive and 2GB on SCSI. There are ways around the 512mb limit and if you want you can always create several partitions. I know a lot of people opt for 4gb SCSI drives and then create two 2gb partition as dive C and D. you may need to set some jumpers on your SCSI card though to enable large hard drive sizes. Here’s a link if you want to learn more about hard drive size barriers.

So if the hard drive was detected and the installer feels it needs formatted you’ll get this option.


Excellent. your hard drive is being detected and you’ve formatted so that’s one thing out of the way. After formatting the PC should restart and then your ready to install DOS.


C: is going to be your boot drive and C:\DOS is the directory that DOS is going to be installed to. It is default and do not change it. I suppose you could but I’m not sure why you would need to or what issues may arise from it. Just hit Enter here.


If there are no errors on the hard drive or disks DOS should install with little difficulty. The three disks should install fairly quickly but stay in the room since you’ll be prompted to swap disks. Once installation is complete remove all floppies from the disk drive and restart. If everything went smooth you should now be booting from your hard drive into DOS.

Okay now that your in a clean install of DOS we need to focus on everyone’s favorite MS-DOS activity, memory management. This is the aspect of DOS that tends to get new users. This activity can get very technical and in-depth. basically in DOS there are several types of memory working and the “conventional memory” or your first 640kb of memory is really what matters most. It doesn’t matter if you have 8mb of ram or 256mb DOS is going to be the same as far as that first 640 and how you can mess with it. basically the amount of free conventional memory or that first 640kb of memory is what matters, its where DOS is and where all the programs or TSR’s (Terminate and Stay Resident programs) that make your mouse and CD drive run goes. unfortunately DOS games also need a certain amount of it available, it varies by games but the more the better and you really want at least around 580-600 for most games to be able to play (though some require even more). So what about the rest of your RAM? well it ends up being seen as XMS which we don’t need to worry about. You can also convert some of that XMS memory to EMS memory which some games need to run BUT converting some of that memory to EMS uses precious conventional memory. The challenge is configuring it in such a way as to have the most free memory since all the other stuff goes there as well. It can be a game of moving around what programs load first and finding the smallest drivers to run your mouse and drives. See there’s also a place called “upper memory” where using a memory managing program we can shift some of those programs from conventional memory to upper memory. Confused yet? Don’t worry, just know that the 640kb called conventional memory needs to be as free as possible.

When your into DOS and at the command prompt which should be C:\ there are two commands you can use that are very helpful in seeing the amount of memory you have available. the first is MEM which displays the amount of conventional memory you have free as well as XMS and EMS. The other command is MEM /C /P which will also display what programs are currently residing in conventional memory. So at the prompt after a clean install type “mem” hit enter and you should get this.


As you can see we have no EMS memory and of the 640kb of conventional memory we are already using 47kb leaving us with 593 which is enough to play a large amount of games. Typing in “mem /c /p” gives us.


This screen breaks down whats eating up that conventional memory as well as what we have moved into upper memory using a memory manager. As you can see here nothing is in upper memory since we have yet to run a memory manager. The first few things “MSDOS, HIMEM, COMMAND” cannot be moved into upper memory (for the most part, I’ll touch on that later). SETVER is mostly useless and can be deleted but it takes so little memory why bother? A few very old games may require it though if that’s a consideration. SMARTDRV is a caching program. A lot of people will tell you that you don’t need SMARTDRV and they are correct. I personally always try to keep it since a few games will install very slowly if it is not running and it is helpful to increase loading times. It MAY cause stuttering on a few games on older CD drives though from the information I’ve found. I would advise keeping it running and rest of the article assumes you do but disabling it will free up the 28kb of memory.

Now if you want any kind of functionality were going to need to load drivers or “TSR’s” to run various things like our CD drives and mouse. There are various drivers for DOS that can be found. You want to find the ones that are most compatible and smallest in size. For reasons of demonstration were just going to assume you want a basic setup with mouse and CD support. which will be what most starting DOS gamers will be mostly concerned about. I’ll also assume a Sound Blaster 16 is being used since it is the most common sound card used in these setups. It fortunately does not require a driver running in memory so we don’t need to worry about that although I have ran a few clone sound cards in the past that did use a small TSR.

CD-ROM – A lot of DOS user’s tend to use the OAKCDROM driver for DOS but I find it to large. I use the GSCDROM driver available for free here. I’ve never had an issue with it detecting a CD drive or reading a CD.

MOUSE – for a mouse the only real option is the CUTEMOUSE driver available for download here. This driver works with all mice I ever tested either serial or ps/2 and the size is a tiny 3kb of memory

If your having trouble figuring out how to install the drivers I can suggest this site. Its focused on creating a DOS PC for the sole purpose of playing the old Space Quest games but it has a pretty good guide on installing drivers and setting them up. He does use different but self installing (and larger) mouse drivers though.

Also keep in mind if your using a SCSI CD drive your going to need different drivers specifically for SCSI. If your using the common Adaptec controller card most of the drivers are still available on their site but you may have to do some digging for specific models.

So assuming were running a basic setup with an IDE drive and basic drivers (mouse, CD-rom) and running a sound blaster 16 for sound. We get all the drivers loaded restart, run MEM command and….


Ouch! and were not even assuming you want to install a network card, have a zip drive always available or run some sort of VESA video utility like UNIVBE. 530kb is a very low amount of memory available if you want to play DOS games and at this point many will not run and give a “not enough conventional memory” error. Investigating further with the MEM /C /P command.


As we can see the added drivers are eating up a lot of available conventional memory. Ctmouse the mouse driver is only eating a measly 3kb of mem but the CD driver (GSCDROM) and MSCDEX the program DOS uses to interface with the CD driver are eating a combined 57kb of memory. At this point I will point out that like the mouse driver there are smaller alternatives. As for compatibility though you may start to have issues. FreeDOS has a much smaller MSCDEX replacement called SHSUCDX though as I mentioned it is not 100% compatible and several games will not work with it, Fade to Black and the CD version of Gunship 2000 being two examples I have found through researching.

Its at this point a lot of questions come up about how to free up memory for games and at the same time still load all the drivers you need to. The simplest solution at this point is to run DOS’s built in memory manager program EMM386 aka memmaker. This the official memory manager and the only one I’ll be covering here. Its compatible with most games with a few exceptions like Ultima VII which no memory manager will work with. There are alternatives such as JEMM and QEMM and so forth that from what I’ve read can free even more memory at the sake of slight compatibility. As the scope of this article is freeing the most memory using official tools it is beyond our scope but if officiality isn’t a concern and you feel you want to try them out, do so.

At the command prompt simply type in memmaker, hit ENTER and the program should start. The first thing it will ask you is if you plan on playing games that use EMS memory. If you choose yes the program will create EMS memory from XMS memory making EMS requiring games available but this will cost us more conventional memory. If you choose no you’ll likely get over 600kb of conventional memory but for our purposes of having the most options will assume “yes” is chosen for the article.

The setup will also ask if you want the “Express” or “Advanced” option. Choose advanced and you should get this screen.


I usually select yes for “scan the upper memory aggressively” and also choose yes for “use monochrome region”. Microsoft actually recommends this to free up memory. It frees up a block that is reserved for a monochrome (black & white) displays. So unless your planning on hooking your machine up to a monochrome display which is pretty unlikely, enable this option.

After you choose the options and go through the process memmaker should restart and ask you if everything seemed to load up fine. Hopefully it did (I personally have never had it not) and you should now have a good number of those pesky TSR’s transferred to upper memory. One more quick thing you can try and not have to be a command line wiz is adjust the “LASTDRV” line in your CONFIG.SYS file to something more reasonable. at the command prompt type EDIT and hit enter and you’ll go to something like this.


select “file” from up top and select “open”. Search for “.sys” and select “config.sys”. your CONFIG file should look something like this (if you’ve already run memmaker).


See where it says LASTDRIVE=Z? just change Z to something like H and it should free an additional 2-3kb of  memory. Unless you plan on having more then 8 drives but you can set it to whatever letter you want but the closer to Z the less mem it frees up. Assuming everything went well and you ran memmaker with the settings suggested and changed your LASTDRIVE value your mem should now look something like this.


So  short of 1kb we are back where we initially were. This would be considered an acceptable amount of conventional memory and most games should run fine. Some games like Elder Scrolls: Arena that require 603kb of conventional memory can be an issue but you can always disable EMS by running memmaker again or type REM before the SMARTDRV command line using EDIT in your AUTOEXEC.BAT file to disable that.


we can see here via the mem /c /p command that much space was freed because the whole CD-ROM driver system (MSCDEX and GSCDROM) were placed in upper memory. At this point we have a highly functional system of 592kb of conventional memory using all highly compatible programs. We have EMS enabled for those games that want it. A sound card for sound, SMARTDRV for fast loading and highly compatible mouse and CD-ROM drivers. This should be sufficient for light DOS users or those just getting into DOS gaming.

Of course much more can be done to free up more memory. The mem /f command is useful for looking at available upper memory space and there are a vast amounts of DOS memory optimization sites available. One of the best is MDGx Max Speed which is an awesome site but slightly disorganized as well as confusing and can be overwhelming for users new to the DOS environment.

Slightly more advanced DOS memory optimization

I do have a 133mhz Pentium DOS machine that I have toyed with a little to try to get the most conventional memory available and still using official MS DOS drivers and no memory management other then EMM386 and I’ll share what I did a little here.


With this setup I was able to achieve 624kb of free memory with EMS enabled along with UNIVBE, SMARTDRV ,CD-ROM drivers and mouse drivers. I achieved this using a much smaller CD-ROM driver, UIDE (5kb) and a program called DOSMAX which moves a few parts of DOS into upper memory that usually wouldn’t go there. As far as I can tell DOSMAX shouldn’t cause any issues with compatibility but its always possible. UIDE works okay for the most part but I’ve had other DOS machines that it just will not load on and I’ve had a few games that had issues running with it though that may be attributed to other things. All in all the system runs very acceptably.


Here you can see it all running as well as the parts of DOS that got placed in upper memory. See apparently upper memory is like an elite clubhouse that only TSR’s can go to and DOS and any of its parts just isn’t allowed.


DOSMAX is like a shady lawyer that sees an opportunity for a discrimination suite but is only half successful in letting some of MS-DOS’s parts inside.


Was that analogy really necessary? Not at all but I wanted to make hasty and badly edited pictures.

Here is my AUTOEXEC and CONFIG files for anyone interested. You can probably use them to help set up a system in a similar fashion and get similar results or base your own memory management off of.



It seems that for a time during the early and mid 1990’s PC manufacturers felt they needed to do a lot of experimenting with PC case design. These days when you buy a PC you generally know what the inside will look like. Sure there is some variation here and there but in general it’s fairly standardized, not so much in the early and mid 90’s. Some PC’s case designs were downright odd and some were like figuring out a Chinese puzzle box to open up. One mild example that I covered earlier was the Packard Bell S605 and its somewhat unorthodox case. The Compaq Presario 9546 much like the PB S605 is also a Pentium 1 based PC and coming from the same era it also is an interesting experiment in internal case design.

from the outside it looks pretty standard and yes it could use a good scrubbing. We have the standard 1.44MB floppy drive and that is the CD-ROM drive that was installed when I purchased it and I assume its not the factory drive. I do kind of like the blue rectangle power button on the right. it also sports some legs that spout out at the bottom presumably to help prevent your tower from randomly toppling over. I suppose that’s a little handy and they don’t really interfere with the operation of the computer

and from the back its pretty standard looking. as you can see if you look at the expansion slots I have installed a video and sound card due to the fact I could not get either of the onboard video or sound working after I reformatted the hard drive and installed a different OS but I’ll get to that in a moment. The ports are all labeled nicely and one thing I do really like are the large tabs on each side that easily unscrew and allow access to the left and right sides of the PC. I kinda hate always breaking out a screwdriver and unscrewing a ton of screws to open a PC and the easy tabs are kind of nice. I should also note the top comes off as a separate piece to give access to the upper drives as well as the PSU. The PSU also seems to be a propitiatory design.

and here is where you may notice the non standard internal design. See, rather than the motherboard laying flat against one side of the case there is a metal divider that goes through the center with the motherboard on one side and the expansion slots on the other and to be honest it’s not really a bad design in some respects and at least on this side it feels like you have plenty of room to get to things. The 9546 uses the AT power connector which was standard for the time as well as a 100mhtz Pentium 1 CPU which is an excellent performer for a fast DOS based PC  or for windows 3.1 and 95. Mine came with 57MB of RAM installed but the 9546 can take up to 136MB according to the spec sheet I found online and this should be more than enough to run anything from the period. The expansion card in the lower right corner is a standard modem I believe of the 14.4kb variety. The onboard video is the ubiquitous S3 Trio64V2, the DOS era video standard which has 1MB of video ram expandable to 2MB. The onboard sound is powered by the Ensoniq chip, same as in the Ensoniq AudioPCI card which is a PCI card that actually offers pretty good DOS sound capability and commendable Windows sound. This computer originally came with Windows 95 pre-installed on its 1GB hard drive and also sported a special Compaq BIOS. Throwing caution to the wind I decided to format the hard drive and install DOS 6.22. which has had some odd affects first of which is this on boot up.

After hitting F1 and booting into DOS everything works fine except I cant get the on-board sound or video running. I’m completely aware this is possibly a driver and hardware conflict but it’s not really a huge problem and there is probably a way around this issue if I played with the BIOS but again, not really a priority since it works fine with the other cards I have installed under DOS.

This would be the opposite side of the case where we have our expansion slots (2 PCI, 4 ISA 16 bit) as well as the IDE connections for the various drives.  despite the seeming openness and space on this side it’s actually a lot more restrictive than a regular PC case as far as securing the expansion cards. The problem is that a standard screwdriver is to tall and will not fit to screw in the screws that secure the cards to the case so you have to use a smaller screwdriver like I have in the picture laying next to a regular sized screwdriver.

This is the Video card I had lying around to replace the Trio64V2. It is a 4MB PCI Trident Providia 9685. I don’t really like Trident cards, they tend to be low end and well…low end. This card is kind of so/so and seems a little better than most Trident video card offerings. Other than VGA it also has a composite as well as S-video connection allowing use of  TV in the case you don’t have a VGA monitor around which is actually pretty useful if you don’t mind taking a substantial video quality hit. Also according to the writing on the top center section of this card it is “stuffed for EDO RAM”, nice.

For sound I’m using a Creative Sound Blaster 16? the model is CT4520 which would make it a AWE64 value but DOS detects it as a sound blaster 16 though I would assume it would see it as a AWE32 or even as it is, an AWE64. Not really the optimal card to stick in this machine but again all I want for it is basic sound and this is what I have lying around, I’ll save the good sound cards for machines I’ll be using.

Conclusion: The Compaq Presario isn’t a bad machine. The Pentium 1 100mhz is a solid CPU and the RAM amount is enough for the time. The case design is actually pretty convenient except for the screwdriver length issue. My biggest problem is the Compaq BIOS that gave me issues when I tried to reformat and install pure DOS. As a windows 95 PC it’s quite passable but there are better more powerful choices.

A lot of people are intimidated by DOS. I was one of those people, I grew up with a commodore 64 and a Amiga in the household so by the time I had a PC it was well into the Windows 95 era. Hopefully this article will help dispel a few myths about the difficulty of setting up a DOS based PC. I am also aware of DOSBOX which is a DOS emulator for use on windows machines and although sometimes emulation is a great way to play games that otherwise may be unavailable it’s still my opinion that it’s no replacement for the feel and nuances of the real deal, even with the latest versions of most emulators I still sometimes find errors in speed and sound. but to each his own I suppose. I’ve created a quick reference page for various PC slot and port types if needed

The easiest, cheapest and all around most compatible DOS PC to put together in my opinion is an early Pentium based system. The one I have assembled uses slightly more expensive parts in an attempt to create an “ultimate” Pentium based DOS machine and perfect for more late era DOS games from the mid 90’s. Usually you can find these older PC’s for cheap at flea markets or yard sales. I found mine for $5. usually they come with windows 95 but that can easily be formatted and replaced with DOS.

this is a typical mid to late 90’s PC case. they loved off white and beige back then.  Has your standard power button, reset button and sleep mode button.


Here’s a rundown of the parts inside. You’ll most likely have these (of some sort) if you picked your PC up at a sale.

1) motherboard, this determines the connectors, CPU’s allowed, max ram and all that good stuff. Mine is a socket 7 board which supports a range of Pentium 1 and AMD CPU’s. You also want to have at least 1 ISA slot (you can easily look up slot types on Google or Wikipedia) since DOS loves ISA slots for sound. My board here has 1 AGP slot 4 PCI slots and 2 ISA slots so its great for my needs. The one I’m using here is a PA-2013 which from what I’ve read is one of the faster socket 7 motherboard produced. It also comes with a massive 2mb of onboard L2 cache memory.


2) power unit, my motherboard has a ATX power connector which are very common but some of these early boards may have an AT power connector which are a bit rarer. you can also snag a ATX to AT power adapter off of eBay for a few bucks.

3) standard CD-ROM drive, you can use a DVD drive but there’s not many if any games from the DOS era that use DVD’s

4) 5 1/4 floppy drive. not really needed since this computer is going to be to fast for a lot of really old games and most DOS games from this era came on 3 1/2 floppy disks or CD anyways.

5) 3 1/2 1.44MB floppy drive.

*Not in the image above I recently installed a 100MB Iomega Zip drive in the bay below the 3 1/2 floppy drive. The zip drive runs off the IDE bus just like the CD-ROM drive. My late socket 7 Motherboard can recognize the drive in BIOS but for operation in DOS it requires drivers and is seen as drive F:. The ZIP drive is convenient because I’ve found there are a lot of files that are just to big to fit on a 1.44MB disk but are not worth burning onto a CD so the ZIP drive is a great and convenient middle ground.

6) Hard drive. I believe DOS 6.22 has a limit of 504MB without using partitions or any other tricks though FAT 16 format can read up to 2GB hard drives on one partition. certain BIOSes can support 2GB partitions though in DOS such as the BIOS on this motherboard. That’s still a lot of space since a lot of games and applications from this era are pretty small. larger drives will work no problem but the OS will only see 504MB or 2GB depending on your BIOS. The first drive I have installed is a 10,000 RPM SCSI drive. SCSI drives tend to be faster and more reliable then IDE hard drives but usually harder to find and more expensive. I believe I have a 8.5gig HDD installed though my OS only can “see” 2GB which is more then enough.

7) This is my secondary hard drive or drive D:\ which is connected to the IDE bus. It is slower then my primary SCSI drive and was formally my primary hard drive. I kept it in my machine after upgrading to SCSI as just a backup and extra space.

8) CPU, I have a 200mhz MMX Intel CPU installed. In my opinion it’s a little to fast and I would recommend something more along the lines of 100 or 133mhz CPU. as you go back and play older games your going to hit speed issues with any Pentium class CPU but anything faster than 200-233mhz and you could start seeing more timing and speed issues showing up in even some early 90’s games.

9) RAM, i have a 128MB stick installed. its a bit of an overkill. most games of the era would be more than happy with 64MB or even 32MB and less

10) cheap extra 99 cent slot fan i grabbed in bulk of eBay. not needed but it helps cool and we wont be using the AGP slot (although DOS should still run fine under an AGP card you may not have as much compatibility since newer cards don’t always support older video standards and resolutions)

11) SCSI controller card. You can also go with SCSI if you add a SCSI controller card. Using quality SCSI controller cards and high end SCSI hard drive/CD-rom drives can increase PC performance since SCSI is less taxing on the CPU. It also makes it easy and convenient to add multiple drives in the future via the external SCSI port available via the SCSI card. Using SCSI hard drives can also overcome the HDD size limit sometimes. On later machines like this one the performance boost is less pronounced then it would be on a 486 or lower but the option to add more external drives still makes it worth wild. I installed a PCI Adaptec AHA-2940w/uw card in the machine as well as a 2GB SCSI hard drive to compliment my IDE hard drive.  This card is well supported and has both external and internal 68 pin connectors as well as an internal 50 pin connector. I added a 8.5GB SCSI (seen as 2GB) IBM hard drive in this system to compliment the IDE Maxtor 9.5GB just to add more space and to test out the drive. using the speedsys utility my speed rating for the IDE drive is 424.81 while the SCSI drive is rated at 819.85 which is almost twice as fast as the IDE drive. I eventually may just go all SCSI with this setup.


12) graphics card, I’m using a S3 Trio64V2/DX PCI card. These cards are not very expensive, fairly powerful and were widely supported in the late DOS era. There is a very wide variety of graphics cards you can use for this era but in my opinion the Trio64v2/DX is the card for the job. There is supposedly a version of the Trio64V2 that uses faster SDRAM labled as a /GX but I have never run across one. You can also use a ISA graphics card but they are generally slower and not as capable. Some motherboards will come with on-board or built-in graphics chip. Generally these aren’t as powerful as buying an add on card. sometimes just installing a add on card will override the on-board video but sometimes you may need to disable the on-board in BIOS.

*After some debate I decided to upgrade my PCI video card to a S3 Virge/GX like this one in my “Building the best all around DOS computer” article.


It has the same 2d core as this Trio/V2 but also more Ram and the ability to run “accelerated” S3D DOS games like Terminal Velocity. Its a really minor thing and any DOS machine will be fine with a trio but I had an extra Virge on hand and decided what the heck.

Also when using either the Trio or any Virge I discovered a utility called S3VBE20. Do a Google search and it should be findable. Its a TSR DOS program that will update your S3 cards VESA from 1.2 to 2.0. This will help when running some games in SVGA. For example it will allow you to chose from many more resolution options in a game like Quake (though if you can actually run the higher resolution modes at a decent frame rate is another matter).

13) 3DFX Voodoo 1. You can also add a Voodoo 1 3d card to this setup. it is a PCI 3d graphics card that you can install in a slot next to your main 2d card (like the Trio64v2). you will need a short VGA cable to externally connect the Voodoo to whatever 2d graphics card you have installed. there are actually a few DOS games that support the Voodoo 3d accelerator card (Carmaggedon, Extreme Assault, Tomb Raider, Ect…). I use a righteous orchard voodoo 1 card with 4MB of RAM. This card uses a mechanical switch so there is an audible “click” when the voodoo activates for a game which has no practical effect but I like it. I recently added this card to my setup so its not in the numbered internal pic located above.

It should be noted that all but one Voodoo 1 cards have 4MB of RAM. Canopus sold a version of the Voodoo called the Canopus Pure 3d and its the only Voodoo 1 card to use 6MB of RAM as well as a TV out. Good luck finding one though as there pretty rare.


14) sound card. For my sound card setup I went through several options before settling. There really are many ways you can go. For this setup I am currently using a sound blaster/daughterboard combo. The current combo I have installed is a Sound Blaster AWE32 paired with a NEC XR385 For the general midi. The AWE32 is backwards compatible with the Sound Blaster 16. The daughterboard is a NEC XR385 which is a NEC relabeled Yamaha DB50XG. These cards are relatively cheap and when attached to a sound cards wavetable header give General Midi support. The general midi standard of the time was set by Roland but I actually prefer the Yamaha general midi sound for certain games and some even specifically support it (Extreme Assault). The sound is mostly the same as the Roland general midi but In certain games like DOOM I think the Yamaha GM sounds better. My particular model lacks a Yamaha FM chip for accurately playing FM tunes in older games but for the era this PC was created for most games will be using general MIDI or CD audio anyways. There are models of the AWE32 that do have genuine FM chips though if you lack a separate PC for older DOS games where you may want an accurate sounding FM capability. I have 6MB of RAM added to this AWE32 but with the superior GM daughterboard you’ll really never use the cards own midi.



AWE32 with NEC XR385 daughterboard attached


Formally I used a Sound Blaster 16 model 2900 paired with NEC XR385 giving me good FM synth and SB16 compatibility. The big issue with this card is the “hanging note” bug that effects almost all SB cards. The degree of the bug varies from card to card but basically it created hanging or stuck notes when used in conjunction with a midi device (either external via the midi port or internal via the waveblaster header). my particular card works pretty well with some games but I get the error with others. Heres a clip taken from DOOM, you can here the hanging note bug as a high pitched “twinkle” sound that should not be there. Listen closely and you can hear it at 0:02, 0:07, 0:13, 0:34, 0:35 and 0:53 in the video here. This card was particularly bad with the “hanging notes” and made games like Daggerfall almost unplayable. After switching to the AWE32 I got the bug far less. In DOOM I’ve only heard it once so far and it hasn’t reared its ugly head in Daggerfall at all yet.

A simple alternative would be to use a Sound Blaster clone card or using two sound cards, one for MIDI and one for digital sound effects. Rather then dealing with installing two cards though I decided I can handle the occasional issue with the AWE32. I did attempt to use a clone card pictured below. It is a Audio Excel card. Unfortunately It failed to install on this computer for unknown reasons. I did manage to install the combo on a separate Pentium DOS PC where it performed fine with no “hanging MIDI” bug. Note though that this card lacks the Yamaha FM synth chip so FM sounds off. There are also reports of some games that just are not compatible or that sound “not right” when running as a Sound Blaster.


Now that all the parts are together there’s a lot to do. You should reformat the hard drive, install DOS (i strongly suggest DOS 6.22) and then install the mouse driver as well as the sound card driver. Most of the motherboards from this mid to late 90’s era should auto detect the hard drive, CD drive and floppy drives. You don’t have to but you may want to replace the CMOS battery. This is a little battery that remembers your settings and the date/time. It’s the same kind of battery they have in a lot of watches but a little bigger. Its cheap and easy to swap out. DOS should be available over the internet if you look hard enough or you can buy a copy online. Sound card drivers should be out there as well. Generally drivers are not required by DOS for graphics cards.

I also use dos navigator 1.51 which can be found for free. it’s a dos navigation program that makes looking around for files in DOS more “windows like” but it should not interfere with DOS compatibility at all. Be aware if its running it does eat some conventional memory.

on to memory. a lot of people have bad memories of running DOS because of frequent memory issues. some games, especially from the late DOS era that our computer is aiming for require large amounts of conventional memory. even when I was a relative newbie to DOS I have to say I ran into very few issues with making conventional memory free. some people say not to run it but if your running DOS 6.22 run the memmaker program and it will optimize your memory. usually that alone gives me almost 600k of free memory. there are a lot of tricks I won’t cover here but just look up how to optimize conventional memory in DOS. load as much as you can into high memory. lean how to manipulate the CONFIG.SYS and AUTOEXEC.BAT files with the EDIT command. one trick to free 1-3kb or more is to change the lastdrive parameters in the CONFIG.SYS file. usually its set to Z but your most likely never going to have that many drives so set it to something more reasonable like H. here is a pretty good but somewhat technical site for optimizing RAM in DOS

I achieved 617k conventional memory with very little effort. that’s enough to run just about any game including Elder Scrolls: Arena, a huge mem hog.

I would say with a little looking around a setup close to this would cost less than $50 even less than $20 or free if your lucky and ask around. it’s most likely a little to fast for really old DOS games but offers good overall compatibility and the ability to play demanding late era DOS games at top speeds and visual settings.

Here’s a video I did on this machine.

Here is the sound setup I used prior which was an AWE32 you can listen to compare

*Updated image with the ZIP drive installed and the upper drives slightly rearranged.



Pentium 200mhz MMX, 128 SDRAM, 1MB L2 cache, 4MB Virge/GX PCI

3dBench – 152.2 FPS

PCPBench – 60.2 FPS

DOOM – 81.54 FPS

Quake – 48.3 FPS

Landmark 2.0 – cpu – 1312 fpu – 3486 video – 24576


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