IBM PC 350 model 6587

The IBM PC 350 was released in the mid 1990’s as an office / home desktop PC. It came in several sub models that used completely different motherboards and CPU’s from a socket 3 486 class up to socket 7 Pentiums all using the same case. In this article were going to look at the sub model 6587 which is the last sub model in the PC 350 class.

The case for the PC 350 is both sturdy but at the same time not extremely heavy. On the front there are LED lights for HDD activity and a power LED next to the large white power button. There is no reset button.

One pretty cool feature is the sliding front cover that slides to the left revealing your various drive bays. There is room for two 5 1/4 inch drives as well as a 3 1/2 bay and two internal 3 1/2 bays for hard drives. In the upper left corner is a cut out for an optional PCMCIA interface which I’ve never seen on a desktop before. Unfortunately mine did not come with this option installed.

My PC 350 did come with an 850MB hard hard drive installed which sounds about right for the time. A CD-ROM drive was an option but mine did not come with one installed. Installing a 5 1/4 drive can be a little taxing and removing the bay bezels can require a lot of force or completely removing the metal drive holders inside which also is not easy due to the assembly being held in by a hard plastic screw.

On the back we have from left to right, a infrared port for connecting an infrared receiver for wireless inferred communication with compatible devices. Next we have two PS/2 ports for keyboard and mouse followed by a serial port, two USB 1.0 ports and a parallel port. Lastly there is a VGA port for the built in video.

There are no screws holding the upper case on and accessing the motherboard is achieved by depressing the plastic tab in the upper left corner of the case and pulling back and then up on the upper case. Thankfully this tab is made from pretty rugged and thick plastic and feels fairly resistant to breaking off.

On the underside of the case is a simple chart explaining the memory configurations as well as a basic motherboard layout and the various switch settings. I always like when PC’s do this as it helps greatly when making basic changes like CPU upgrades.

Here is a view of the drive bay assembly removed from the case as well as the hard plastic screw that needs to be removed to get the metal assembly out.

Now lets take a look at the motherboard and relevant parts.

The PC 350 motherboard does use a standard lithium battery to store CMOS settings. In the image below is is obscured by the IDE cable.

 

1) CPU – My model 6587 came with a Pentium 133 but is easily upgradable. The chart found on the case underside gives settings for installing up to a Pentium 166 but online sources indicate a Pentium 200MHz classic or even a 166 or 233MHz MMX chip can be successfully installed though you may need to experiment with motherboard switch settings (Wikipedia suggests the 75MHz setting should work for 233MHz).

The MMX chips take a lower voltage from what it appears the board can provide so use caution if your going to attempt an MMX install. For a Pentium 200 classic the jumper settings were not present on my jumper sheet but through trial and error I found the settings for the Pentium 120 allowed for 200MHz operation with the P200.

The CPU’s on all of these machines are fanless and only come equipped with a passive cooling heatsink, though a rather tall one.

The instructions and all paperwork only refer to 3.3 volt Intel Pentiums CPU’s being compatible with some sources claiming Cyrix and AMD chips to be incompatible though I was able to upgrade my board with an IBM branded Cyrix 6×86 PR 166+ CPU without issue. I just made sure my CPU was labeled as requiring 3.3 volts (most Cyrix 6×86 CPU’s seem to require only 2.9 volts).

*Correction* The above chart refers to the Cyrix / IBM CPU as a “PR 166+” as it should be labeled as a P166+

2) RAM – The PC 350 has one 168 pin RAM socket as well as four 72 pin RAM sockets for memory expansion. You can expand the memory up to a total of 192MB and the convenient chart found on the underside of the case lid has a graph showing the advised memory configuration for the desired memory amount.

My PC 350 came with 32MB of memory installed via one 16MB 168 pin stick and two 8MB 72 pin sticks. I originally thought I would try using a single 32MB or 64MB stick of 168 pin memory and forgo the 72 pin sticks but none of my 168MB sticks would physically fit the 168 pin slot. I tried several sticks and they all were physically very slightly off and would not install. This is because I later discovered the 168 pin slot is keyed for 5 volt SDRAM which is not compatible with the 3.3V (the common used SDRAM).

3) L2 cache slot – L2 cache on the model 6587 is via a COASt module fount next to the CPU and can accept either 256KB or 512KB of L2 cache. Mine came with a 256KB stick though I needed to remove it and clean the contacts before it was recognized.

4) Video – The PC 350 comes with a S3 Trio64V+ chip on the board along with the ability to expand the memory from 1MB up to 2MB. The Trio chipset is an extremely DOS compatible chip proving excellent 2D support and compatibility for DOS and Windows 9x.

5) Riser card – The PC 350 uses a riser card in order to provide both PCI and 16-bit ISA expansion slots. In total the riser provides three PCI and five ISA slots though three slots are shared PCI/ISA slots and two are dedicated ISA slots. The opposite side of the riser provides for one of the stand alone ISA slots as well as a connection for power.

6) Floppy/IDE -The 350 motherboard provides for standard floppy connection as well as two built in ATA-2 IDE connectors for a total of four IDE compatible devices.

7) Switch – This is the switch used mainly for selecting your processor speed. Thankfully the chart on the underside of the case provides the settings and switch configurations should you decide to change CPU’s. The chart provided does come off as a little confusing though as It does not list actual FSB settings or provide a setting for 200/233mhz CPU’s. The Wikipedia entry on the PC 350 advises setting the switches to the “75 MHz setting” for a 233MHz Pentium.

8) PSU – The 350 motherboard requires three PSU connections to the board. Besides the standard AT connection the 350 also requires an additional AUX connection as seen below.

The IBM PC 350 makes a fair retro computer. It excels at DOS retro gaming and needs very little besides an ISA sound card to have a very compatible machine. As a Windows PC it is quite acceptable and a PCI 3D accelerator card such as a Voodoo would do wonders. The BIOS tends to be fussy though and when I made ANY changes including simply unplugging the mouse the machine demanded I enter the setup feature upon restarting and change/save the new settings. There are other annoyances such as the extra connection needed on the power supply as well as the slightly picky 168 pin RAM slot.

The case itself is quite nice offering a sturdy design, decent bay expansion as well as being easy to get into. I also like the sliding piece on the front so you can cover up your ugly discolored drives when not in use. Adding drives though requires some disassembly and is a hassle.

For a DOS PC the IBM PC 350 will serve you well though for Windows it’s passable but there are much better options. As a side note I could not get Windows 95 or 98 to install on my machine. This was due to some sort of driver conflict at the Windows splash screen I was never able to resolve. The machine IS Windows capable however and this problem boiled down to my particular machine.

Project Computer: The Pentium-75 PC, for that old-timey Pentium feel

Machines based around the socket 4 Pentium-60 and 66 make for a fairly fun and unique DOS computer. They have the FPU power of the Pentium yet are slow enough that they will run most DOS games meant for the ubiquitous 486-66DX2. As neat as a socket 4 system is (If you want to read about one check out an article I wrote on the subject here) They can be pretty expensive and hard to find these days. The earliest Pentiums also have their fair share of quirks and can be unreliable. With this project I wanted to make a Pentium based system as cheap as possible and as close to the performance as possible to the original Pentium-60 and Pentium-66. The main goal of this PC will be to play early 90’s 2D DOS games and applications as well as early Windows games. Of course a lot of this can be achieved with a faster CPU and slow down programs or disabling various caches in BIOS to slow down a CPU but that’s not really my style so were going to create a PC based around the next logical option if you can’t acquire a socket 4 board which is the Pentium-75.

The Pentium-75 was released in September of 1994 for the new socket 5 but it is also compatible with the newer socket 7 form factor when it was later released. Unlike the 5v Pentium-60 and 66 the Pentium-75 ran on 3.3v and was cooler running and much more reliable. That said with this build we are going for a mostly 1994-95 look and feel for this project. My focus is using mostly period parts when I can for a decent DOS and Windows 3.1/95 PC with an emphasis on 2D gaming rather then early 3D. I’m not necessarily trying to make this project an “ultimate” build for the era, just something that feels appropriate. This also lets me experiment with different hardware.

The case I decided to use for this project is a little beat up but I think it has the right look for this machine and I wanted to go with a desktop style for this build. I would of liked to add a 5 1/4 1.2mb floppy drive but unfortunately the holding brackets for the two vertical 3 1/2 bays are missing so I could not mount anything for them forcing me to use only the three 5 1/4 bays. I had to use the middle bay to mount the hard drive as no other space was available for mounting. I wish I had another one of those 1.4mb / 1.2mb combo floppy drives or 3 1/3 floppy / CD combo drives available. The HDD I’m using is a older drive of about 3gb, thankfully the BIOS in on this motherboard supports larger drives and I am able to use a full 2gb in DOS.  I did go with a newer 32x CD drive since I can’t find any IDE CD drives from that time frame in my stash that work but this drive operates just fine if not a bit loud. I’ve also adjusted the jumpers on the frontal LED display to illuminate a pleasant “75” when power is turned on via the power button. Under the LED display are two more buttons for turbo and reset. Turbo features rarely if ever work with Pentium CPU’s and not to long after the 486 era the jumpers stopped appearing on motherboards.

Nothing special about the rear of this case and it’s mostly as one would expect from an AT style case.

Taking off the cover reveals the innards of this particular PC. I originally wanted to go with Socket 5 for this build but lacking a working socket 5 board I opted for a slightly newer AT style socket 7 board. I suspect running this chip on a socket 5 board possibly would of given slower results but this of course depends on boards and chipsets. Even though the faster Pentium-75 has an advantage of a slightly newer architecture and a 9mhz clock bump I was very curious how much of an effect the lower 50mhz FSB of the Pentium-75 with a 1.5 multiplier would have on it compared to the Pentium-66 running on its 66mhz FSB.

As you can see above there is no way to mount anything at the two 3 1/2 cutouts.

The Motherboard I’m using for this build is an Aptron International PM-8600. This is an AT style Socket 7 board with 512kb of L2 cache on the motherboard as well as supporting up to 512MB of EDO RAM in either 72 or 168 pin slots. There is built in support for four IDE devices via an ATA-33 controller. The board also sports four 16-bit ISA and four PCI slots for expansion. I feel the overall look and capabilities of this board fit the mid 90’s era we’re shooting for.

Now that we know the motherboard we are using for this project lets take a look at the other components.

CPU – Obviously the CPU we are using is the Intel Pentium-75mhz. This CPU came out in 1994 and was really seen as the first reliable and “serious” Pentium chip as the earlier Pentium 60/66 chips had issues with reliability and heat. This CPU should be as fast as the fastest 486 chips with superior FPU performance. The Pentium-75 operates on a lower 50mhz FSB utilizing a 1.5 multiplier as opposed to the 60 and 66mhz FSB of the earlier Pentiums running at the same speed as the FSB.

(image courtesy of Wikipedia)

some models of the Pentium-75s came with the same gold top as the earlier Pentium 60/66. even though with a mounted heatsink/fan this makes no aesthetic difference compared to a Pentium with a ceramic top I happened to have a gold top CPU so this is what I used in this build.

RAM – The PM-8600 board supports both 72 pin DRAM as well as 168 pin SDRAM RAM as well as the faster EDO RAM variant. I went with 32mb of 72 pin EDO RAM for my build. 32mb is more then enough memory in most cases for the 94/95 era. Using 168 pin SDRAM is likely much easier to find, faster and cheaper then 72 pin so it’s nice to have that option for those looking to construct a similar build but I opted for the older 72 pin variant simply due to the fact I had extra in my stash and it gave the machine a more internally oldschool look.

Video – For a video card in this PC I wanted to experiment a little and try a few different cards outside of my “go to” cards. I also wanted to specifically go for a 2D PCI card without any 3D capabilities as in the mid 90’s combined 2D/3D cards hadn’t completely taken off yet and many early PCI cards were produced that were 2D only though you could pair them with early 3D accelerator cards like the Voodoo 1 and 2.

The video card I went with for this build ended up being the ATI Mach64 released in 1994. Despite the Mach64 being one of the more sought after ISA and VLB cards the PCI implementation as my chart will show shortly is certainly not the fastest early PCI card but it is pretty well known.

As I mentioned earlier I wasn’t necessarily going for the “best” parts for this era and I did want to experiment a little. ATI whom eventually was bought out by AMD is known for making some pretty good video cards throughout the 1980’s and 90’s and the Mach32 and 64 were known to be pretty decent 2D accelerator cards when running in Windows 3.1 and Windows 95. As for DOS games the Mach64 scored dead last in my benchmarks when put up against several other 2D PCI cards from the era.

Benchmarks performed on the Aptron International PM-8600 motherboard with a Pentium-90mhz. ATI Mach32 also tested but statistically identical to Mach64. All tests done using “vanilla” results without the aid of enhancement programs such as FastDOS

In all of my benchmarks the Mach64 fell behind similar offerings from Tseng Labs, IGS and S3. I have also read sources that claim the Mach32/64 cards have hit or miss compatibility with certain DOS titles producing graphical glitches. Though this is true with all cards with S3’s offerings widely sighted as the king when it comes to compatibility the Mach32/64 series and ATI cards in general may be a little worse overall. So far with my own testing I have seen no graphical issues though the number of games I’ve tested have been relatively small. As mentioned earlier though usage in Windows 3.1 and 95 should be good. I can confirm myself that when using the card under Windows performance in the GUI felt snappy.

Keep in mind like many cards there were variations of the Mach64 offering more and faster video RAM as well as minor chip revisions. There seems to be at least eight major chipset variations for the Mach64. I have the GX variant which offers enhanced video playback capabilities over the original card. I went with this card despite the alleged deficiencies because overall it still performs adequately and I was not going for a power machine. In the case of this build the slower FPS produced by the Mach64 actually helps to keep this machine in line with our late 486 era / Pentium-66 performance goals.

Sound – I really struggled with choosing a sound card for this system as I wanted something that felt correct for the era but I also wanted to experiment a little with different cards. In the end though I went with a good old Sound Blaster 16 CT1740. This is an older SB16 with manual jumpers to configure settings and a dial to control volume. The CT1740 is a fairly “noisy” card so prepare for buzzing at higher volumes as well as an assortment of “pops” now and then during game play. despite the “noisiness” I find myself liking it very much and it tends to “just work” with very minimal setup hassle. The card features a true OPL FM chip for FM synth and has pretty good compatibility with older games that supported the Sound Blaster Pro. Usually the CT1470 is free of the dreaded hanging midi bug though mine has DSP ver 4.7 so unfortunately mine does, though I was able to get around this by adding a midi card which we will take a look at next.

The empty socket is for the ASP chip and the vast majority of older Sound Blasters seem to lack this chip. The capabilities of this chip were only used in one game to the best of my knowledge. That game being the 1993 DOS title TFX: Tactical Fighter Experimental, so we’re not really missing out on much due to its absence. You can check here to get a guide on how to set your jumpers to fit your requirements.

MIDI – When it comes to midi, whether using a wavetable board or an external module my CT1470 does have a few issues. One is since my card does have a later DSP version it does suffer from hanging midi notes though keep in mind that cards with DSP version 4.5 and lower will be bug free. The other issue with all of the Sound Blaster cards is that they do not support games that require “intelligent mode” which includes many high profile games. There are software solutions such as SoftMPU but this creates a small amount of processing overhead and I just tend to prefer hardware solutions when available. Midi support in my opinion is pretty important for this PC since a huge amount of games supported MT-32 and General Midi standards by the mid 1990’s.

The midi card I had available and opted to install in this machine is the Music Quest MQX-32m.

Music Quest MQX-32m with dongle

The MQX-32m is a Roland MPU compatible midi clone card meaning that it basically works just like if you were using a true midi card from Roland. I run this card along side the sound blaster to handle all my midi needs via external midi modules while the Sound Blaster 16 handles digital effects as well as FM synth. The MQX-32m supports games that require intelligent mode and suffers from no hanging midi bugs. It is important to note that this clone card is not 100% compatible and some Origin games such as Wing Commander will lock up when you attempt to run them using this card. Since the focus of this build is later games (due to the high CPU speed Wing Commander would be unplayable on this machine anyways) I’m not very concerned with the compatibility and this card should work fine with just about every game this PC is intended for.

The MQX-32m is a very interesting card as it supports many features and even has two Zilog Z80 chips for dual midi output. The bulk of these features though many of which I have no idea what they do are more geared to music applications so for our purposes it’s good enough that the card supports intelligent mode midi and solves all our midi issues that using the Sound Blaster alone would of created. I currently have my MQX-32m configured as address 330 and IRQ 2, being careful to not conflict with my Sound Blaster 16 card settings. a chart detailing how to set the DIP switches to select those settings can be found here.

So now that we have looked over all our hardware how does this machine perform and also how does its performance stack up to my socket 4 66mhz PC? Lets take a look at the benchmarks.

As we can see from the benchmarks that despite a slightly lower overall Front Side Bus the newer Pentium-75 pulls ahead in all tests. In games though the performance boost isn’t terribly noticeable as the boost is generally around or under 5 FPS. In some games where the FPS is lower like Quake the extra 5 FPS is far more noticeable then say DOOM where both machines are pulling 30+ FPS. Synthetic benchmarks tend to favor the Pentium-75 more but those kind of results are usually expected from synthetics. As I mentioned earlier you can get somewhat different results depending on what motherboards you use but I feel results will generally follow the trend above. These results seem to indicate that gaming on a Pentium-75 machine should give a more or less similar experience to gaming on a Pnetium-66 machine without the headaches and with significantly lower cost involved.

For some more comparisons I decided to also make a chart including results from my Pentium-66 PC with my preferred PCI ET6000 card installed.

From looking at the tests the ET600 makes a pretty big difference and in many places helps close the gap with the Pentium-75 machine. Gains in Quake are very modest which makes sense as I believe that game to be more CPU intensive then video card. I wasn’t able to test the card in the Pentium-75 PC due to the fact that when installed the machine failed to move past POST and would produce a black screen regardless of how I manipulated settings in the BIOS. The card did work when I had a faster Pentium-90 installed and although I haven’t gone back and reinstalled that CPU to test this theory my best guess is that my ET6000 just doesn’t like the 50mhz FSB the board uses with a Pentium-75 installed. Interestingly my S3 cards also fail to work on this board when a Pentium-75 is installed while my ATI Mach cards as well as my IGS card work flawlessly.

Overall I think this machine achieves its goal of being a mid 90’s PC very well and comes very close to approximating the feel and performance of an original Pentium with none of the fuss. Of course the video card can be upgraded to a faster 2D card or even a 3D card if you so choose. I find performance with early 90’s titles like Doom and Wolfenstein 3d to be rather good. Even games like Quake can be somewhat playable at lower resolutions if sub 30 frame rates don’t bother you to much. I’ve also been playing a lot of slower paced strategy games like Panzer General on this machine which it handles perfectly. I have found even a Pentium-90 plays the movie clips in Panzer General a bit to fast but on the Pentium-75 everything seems to play at the correct speeds and game play is very fluid. Windows 3.1 and Windows 95 feel fairly snappy to navigate overall and I haven’t run into any major issues.

There isn’t any super compelling reasons to specifically build a Pentium-75 PC on its own if all you want is a retro game machine. If you want a more classic PC for retro gaming then a 486 system is advised and if you want a retro rig with a little more power then why not go for a Pentium-133 or 166mhz with a 3d capable card? That said if you want to build one just for the experience or maybe due to nostalgia for a 75mhz PC you had in earlier years it will still make a very serviceable retro machine capable of playing a large amount of games from the later DOS and early Windows years.

 

Socket 4: The cutting edge of 1993

In 1993 the Computer world was beginning a new era. The venerable 486 was ruling the roost and hard core PC gamers were enjoying 66mhz DX2’s and VLB bus video cards. A new era though was just around the corner featuring a world of improved 3d gaming and performance due to a new expansion slot type and a new CPU. This was the dawn of the Pentium.

This new generation of CPU’s named the Pentium (just a fancy name for Intels 5×86 chips brought about due to the fact Intel could not trademark a number) required a new socket type to support them. This socket was the socket 4. With the Pentium a new type of expansion bus was also starting to appear more and more. This was the PCI bus were all still familiar with today. The PCI bus was not exclusive to the Pentium and could be found on late model 486 motherboards but starting with socket 4 is when it began to be considered standard on motherboards.

Socket 4 supported only two chips. The first generation Pentium 60mhz and the 66mhz. Looking back they were a little underwhelming, expensive and always ran hot at 5 volts but they were the cutting edge in 1993 and they offered significantly better FPU (or floating point math) then the 486 chips which the new crop of 3D games would take advantage of. To compare, the original 66mhz Pentium was about equivalent to a 100mhz dx4 486 chip.

In this article I’m going to take a look at what would be a typical high end socket 4 build from about 1994, so pre-windows 95. Building a 94 period correct machine rather then a 93 one opens up many more possibilities since PCI really didn’t come into its own until 94. In 93 there weren’t a lot of PCI cards available and in all likelihood someone that splurged in 93 on a socket 4 board may of been stuck with a ISA video card for few months.

This would be a case very typical of the era. By this point the desktop form factor really seemed to be fading away as far as home computers go and a majority of new PC’s in homes were of the taller but usually less internally cramped tower design. Of course an IDE hard drive like the one I have installed was standard by now as well as the 1.44MB 3.5 inch floppy drive. A lot of machines from the era still had a legacy 5 1/4 inch 1.2mb floppy drive as well to support older software or games you were likely to still have from a previous 486 or 386. The CD-ROM drive was also starting to become standard fare now as more titles were being released in the format and popularity of the CD was bolstered from the hit game Myst that was released the year before in 1993 on CD-ROM.

The motherboard I’m using in this machine is a socket 4 Intel PM-900 with what I believe is the Mercury chipset. It still has many features that were more common with a 486 motherboard such as on board l2 cache and an AT style keyboard. It does feature three of the then cutting edge PCI expansion sockets and four older 16 bit ISA slots. To be honest I was initially surprised by the lack of features on this board. Even if it was a low end socket 4 board you would expect manufactures to want to go all out for something that at the time was an expensive state of the art board. a PS/2 mouse port or connector for a header would of been nice as well as on board IDE or floppy connection. Many of these things were even starting to show up on 486 boards of the time.

There are also some interesting peculiarities on this board such as the inclusion of a connector for a turbo led but no turbo switch. Instead of a jumper to select if your using the 60 or 66mhz CPU this board requires you to swap out the oscillator not unlike many 386 era boards. Also the board features jumpers for the PCI slots and these assigned IRQ’s. I have never noticed this on any board before.

Taking a closer look

1) CPU – The real star of the motherboard was the cutting edge Pentium processor. You had only two options with socket 4 and those were the two early P5 Pentiums that came in either 60mhz or 66mhz. Mine is the faster 66mhz. both these CPU’s ran at 5.0 volts when as all Pentiums after ran at 3.3 volts. You did have one option though for upgrade and those were the socket 4 Pentium overdrive chips. these chips would boost a P60 system to 120mhz and a 66mhz system up to 133mhz which is pretty significant. Unfortunately these overdrive chips are pretty uncommon and when found expensive. These upgrade chips also weren’t released until later in 95 or 96. The Pentium 66mhz is roughly comparable to a 100mhz dx 486 though with a superior FPU performance as I said earlier. These chips did noticeably outperform the gaming standard of the day which was the 486 66mhz DX2 but later 486’s like the 133mhz 5×86 from AMD with a Pentium rating of 75 easily beats the 66mhz Pentium in everything except Pentium optimized games or games that utilize FPU operations such as Quake. It has also been found that 83mhz Pentium overdrives used to upgrade 486 boards will also outperform a true Pentium 66mhz. to change the CPU from 60mhz to 66mhz or vise vera there is no jumper. you need to change the oscillator. The oscillator is obscured in the image above by the wires but its located above the CPU and to the right of the large chip under that bundle of wires.

2) L2 cache – the on board L2-cache, all of the Pentiums up to the Pentium II lacked on chip L2 cache so as before L2 cache was accessed from the motherboard. The PM-900 supports up to 256k of L2 cache which is pretty standard for the time and the amount I have installed.

3) RAM – this board supports up to 192MB of 72 pin DRAM via six slots. As far as I can tell it does not support EDO RAM. Its a bit of an unusual number but 192MB would of been an outrageous amount of RAM for the time. I have a more conservative 32MB’s installed which would be more common for the time on very high end pimped out builds like this one. At the time though many machines still happily ran 8mb or 16MB’s so even this is overkill.

4) AT power connector

5) AT keyboard port

6) CMOS battery – this board uses the infamous Dallas real time clock. these clocks were basically lithium batteries in a hard plastic shell. Though they don’t have the same level of leaking risk as the old barrel batteries they are sometimes pretty annoying to replace. they can be hacked to allow for cheap and common lithium battery replacements.

Now I’m going to go over some expansion cards that would be pretty common for a machine of this type. I’m not going to talk about modems cards cause they bore the hell out of me but a PC of this era would usually have some sort of ISA or maybe PCI networking card or modem.

Multi I/O – since there is no IDE or floppy controller built into this particular board I needed a I/O controller. This is the one that came with my board. Its a Winbond chip based card and nothing special but it gets the job done for floppy and IDE support as well as giving me a serial and parallel port.

Video – The choice of early PCI video cards seems to come down to two brands, ATI and S3. You also need to ask whats more important to your specific built. DOS performance or Windows (3.1) performance. Some cards are better in DOS and some Windows. The ATI mach64 supposedly was released in 94 but all the cards I found had a BIOS date of 1995. This left me with a PCI ATI Mach32 and an S3 Vision 864. after some benchmarks the 2MB Vision 864 did come out ahead in DOS but I never tested in Windows. The Vision 864 like the trio that would come later was a great card for the time offering excellent compatibility with games and other software. Other options are the venerable et4000 which should of had an early PCI version available.

Sound – There are a multitude of option for sound such as the PAS16, Adlib gold or Gravis Ultrasound that were out in 94 but all of said cards are rare and expensive. The sound Blaster 16 line on the other hand was widely available and almost all games supported it. My board came with Acer Magic S30 which is just a SB16 that used a early version of the Vibra chip. This card has a real OPL FM chip, some various CD drive headers as well as a wavetable connector for a daughter board. Its not as fancy as the other cards but its a hell of a lot cheaper and just about everything supports it. This card does suffer from the “hanging midi” bug though. I should point out on this build I actually am using the on card controller of this sound card to run my CD-ROM drive.

So, is a socket 4 machine worth it to collect now and was it worth it back then. To address the second question first, No. The Pentium 60 and 66mhz were insanely expensive when they were first introduced. Throw in the fact they ran hot and were fairly unreliable and they just weren’t smart buys, even with the power boost. Consumers were far better off waiting for a 100mhz DX4 or better yet a AMD 133mhz 5×86. Many early software wasn’t yet optimized for the Pentium or took advantage of its superior FPU abilities that only later 3D games like Quake would heavily use. Now are they worth having presently as part of a retro PC collection, maybe. The price of these CPU’s and motherboards keeps creeping up as they become more and more rare. For practical use though in an actual running retro game PC there more of a novelty and best avoided. A retro gamer is far far better off with building a socket 5 or 7 machine as those Pentiums are more powerful, cheaper, and far more reliable then the socket 4 types.

benchmarks Pentium 66mhz, 256kb l2 cache write-through, 32mb fpm RAM, s3 Vision 868 2MB

3DBENCH – 56.4 FPS

PCPBENCH – 17.6 FPS

DOOM – 37.78 FPS

Quake – 14.1 FPS

same setup with a ATI Mach32 1MB

3DBENCH – 49.0 FPS

PCPBENCH – 16.7 FPS

DOOM – 36.03 FPS

Quake – 13.6 FPS

Pentium 66mhz, 256kb l2 cache write-back, 32mb fpm RAM, ET6000 4mb

3DBENCH – N/A

PCPBENCH – 18.3 FPS

DOOM – 40.6 FPS

Quake – 14.8 FPS

Gateway 2000 P5-120

I really didn’t need another Pentium 1 system but I have a soft spot for the Gateway 2000 especially when they come with matching monitor and keyboard.  Gateway 2000 is what Gateway used to call themselves up until the late 1990’s and they made some pretty quality Pentium 1 and 486 machines. The one I picked up here is from the middle of the 90’s. This is a solid machine that I received from a family and from what I was told had seen much use and still was almost stock with almost all the parts coming from about 1995 with the exception of the CD-Rom drive and some added RAM. The machine still booted up fine from what appeared to be the original hard drive and ran like a champ without having to do anything.

The version I have is a desktop case. I think most of their models also came in a tower configuration as well. Its a nice sturdy case and is nice and high to allow for 3 5 1/4 bays which is really nice. I’m not a huge fan of the vertical orientation slots for the floppy drives but its okay. Its good for saving space but this case is large enough that I don’t think a traditional horizontal orientation would of made any difference except maybe interfering with the gentle aesthetic  “bump” the left side of the case that protrudes. Unlike the Packard Bell machines Gateway had a sane model naming scheme.  P5 I assume designates  a Pentium Processor inside and the 120 after that should designate the CPU speed or mhz. So unless someone has changed CPU’s this machine should sport a Pentium 120mhz CPU. Power button is on the right and we have a big round reset button on the left next to the never used case lock. Below that you have your standard power and HDD light but there is also a turbo light but there’s no turbo button on the case and no keyboard combo I can find that initiates the turbo (slows the computer down). So until I discover otherwise I assume this is just because they used the same case with a different badge for the 486 line.

The rear of the machine is pretty standard. We have two ps/2 ports for the keyboard and mouse though the ports are not color coded on this machine. Above them are two serial and one parallel port. We have 7 expansion ports on the back. A few are specifically labeled for video, joystick/sound and network but you don’t have to put those cards in those slots but I have for looks reasons.

This is actually how the board looked when I first opened it. Covered with years of dust. At least there were no dead insects or mice.

And here is the board after removing most of the dust.

1) CPU – The motherboard uses socket 5 as well as a Pentium 120 which is just as well as that’s the fastest commonly available CPU for that socket. The Pentium 120 is a solid CPU being fast enough for earlier Windows stuff and more then sufficient for most DOS applications without being to overkill. As you can see mine did not come with a fan on the heatsink which though I wouldn’t recommend is apparently fine since this thing ran for a long long time without. I suppose if you had one lying around you could toss in a uncommon Pentium overdrive or Pentium overdrive MMX for a boost of up to 180mhz maybe 200mhz. This motherboard uses the Intel 82430fx chipset.

2) RAM – my machine came with some odd amount of RAM, I want to say 40 something but originally from what I found they came factory with 8 or 16 mb of RAM. I have expanded mine to 64MB but the total the board can take is 128mb. This machine can accept FPM or faster EDO. I went with FPM because I have so much of it here.

3) CMOS battery to keep Bios settings

4) connectors for the serial/parallel ports

5) AT power supply connector

6) floppy drive connector

7) Two IDE connectors

as for L2 cache my particular board came with none and no sockets to add any. There are some vacant suspicious spots right above the CPU that looks like cache chips may belong there but running cachechk program confirms no l2 cache is present on the board.

The board also sports three PCI and four 16 bit ISA slots which is nice for DOS/Win 9x expansion options.

Here are the expansion cards that originally came with this machine. I highly suspect these are also what came factory with this machine. Top left is the modem and to the right of that is the video card which is a PCI S3 Trio64V+ which is an earlier s3 trio card but still very compatible for DOS games but offers no 3D acceleration. On the bottom is the sound card that was installed which is a Sound Blaster 16 CT2800 that uses the less noisy Vibra chip and has a OPL chip for FM. Its a good DOS sound card and adequate for Windows 9x.

I did end up doing some upgrading. I added a fan to the CPU heatsink. I replaced the SB16 with an AWE32 since I have a few of them lying around. I originally switched the tri64V+ with a tri64v2 thinking the same drivers would work for both but I was wrong. In the end I stuck in a Matrox Mystique I had left over from my vintage 3d article to give the machine a nice graphical boost (while hurting the DOS compatibility somewhat) and add some 3d acceleration capability. I also transferred the original HDD which was still running the origional Windows 95 that came packaged with the machine (I think it was about 1.5GB) to a removable bay. so the new loaded motherboard now looks more like this.

Its a nice sturdy system. Personally I like the classic G2K machines and this Pentium 120mhz rig has potential to be a great DOS box for someone.

Anatomy of a Pentium based DOS PC

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

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 http://www.mdgx.com/mem6.htm

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.

Benchmarks

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