Skip navigation

Tag Archives: AMD DX-40

dlc3

Previously on this blog we have discussed both what I think is an “ultimate” or at least near “ultimate” 386 PC in the Anatomy of a 386 article and we also talked about pushing certain sockets beyond their intended scope such as with the 486 and Socket 3 motherboards and pushing their limits  and I wanted to do something similar with the 386. In this article were going to take a look at the Cyrix 486DLC chip, a drop in replacement chip meant to upgrade a 386 class motherboard with a 486 class CPU. Were going to look at one of the more common DLC chips, the Cyrix DLC-40, run some benchmarks and put it up against the king of the 386 chips the AMD 386-40.

First lets take a look at the test PC and then the CPU’s will be testing.

dlc4

This is the 386 PC will be testing the CPU’s on.

dlc7

I could not identify the motherboard but it’s based off the Opti 495XLC chipset and is loaded with 128kb of L2 cache and 8MB of FPM RAM. For video I am using a Tseng Labs ET4000 ISA video card and I have a Sound Blaster 2.0 installed as well although it will be unused for the benchmark tests. My memory settings are fairly standard and I didn’t mess with them much from the defaults. AT bus divider set at 5, memory timings set at 2-1-1-1 and wait states set to 1.

So lets take a look at the two CPU’s will be testing today.

First up is the king of the 386 chips, the famous and beloved AMD 386DX-40.

dlc6

The 386DX-40 was a very reliable 32 bit 386 chip made by AMD and is very well regarded for its speed and reliability. This is the fastest true 386 made and is overall very capable. It though, like all true 386 chips has no L1 cache memory on board.

The second CPU we will be putting it up against is the Cyrix 486DLC-40.

dlc5

The DLC-40 created by Cyrix was intended to be a drop in upgrade CPU for 32 bit 386 class motherboards which in essence gave 386 PC users a 486 CPU upgrade. It essentially is a supped up 386 with 486 code inserted and 1kb of L1 cache added on the chip. There was also a more common 33mhz version like this guy.

dlc33m

as well as later DLC chips made by Texas Instruments and IBM which added even more L1 cache. The fastest of these chips is an IBM triple clocked DLC rated at 100mhz that supposedly is about equal to an Intel 486DX-66. Due to licensing agreements though I believe IBM was only able to sell these chips imbedded as part of a motherboard or upgrade kit.

There are also SLC variants which are 16/32 bit hybrids designed to be more compatible with older motherboards where as DLC variants are true 32 bit.

The on board L1 cache memory of the DLC is a huge advantage over the AMD 386-40 so on all the benchmarks I tested the DLC chip twice, once with the cache enabled and one again with it disable so we can see how much of a difference this makes.

The unidentified 386 class motherboard I’m using is a later model and supports the DLC chips in BIOS. Here is a shot of the specs as I boot up.

dlc8

Notice the BIOS recognizes the DLC chip as under “main processor” it is listed as a Cx486DLC. Many older 386 motherboards  may not recognize the DLC chip properly and simply report it as a 80486SX. You may also need to run a setup utility with these older boards to fully utilize the DLC chip.

My BIOS also has the option to enable/disable the internal L1 cache on the CPU though for reasons I cant figure out this option does not work and the l1 cache is enabled automatically regardless of how it is set here.

dlc1

 

Failing this you can always disable/enable the internal L1 cache via software. I used the Cyrix cx486 utility which allows you to easily enable/disable the L1 cache by the C button. Just be sure to hit W to write your choice to the registers before exiting the program.

dlc2

So without further adieu we have the benchmarks. The programs I used were all pretty standard, 3D Bench, PCP Bench and DOOM. Below is a bar chart to better illustrate the performance of the two chips and I also added a 33mhz Intel 486 results from a similarly spec’ed 486 machine using the same amount of L2 cache and the same video card to compare.

dlcgraph

The results are basically what we would expect with the DLC handily defeating the AMD 386-40. DOOM seems to benefit the most from the L1 cache as the difference between the 386-40 and DLC with cache disabled is only .6 FPS but with cache enabled its a 2.5 FPS difference.

you’ll also notice the DLC does pretty well compared to the Intel 486DX-33 even tying it in PCP Bench. After some optimization I managed even more performance gain.

After setting wait states to 0 and the AT bus divider to 3 I was able to get the following results out of the cache enabled DLC-40

3D Bench    – 22.1

PCP Bench –  5.5

DOOM        –  10

You can see with these results the DLC surpasses the DX-33 in all but DOOM.

graphdlc2

The folks over at Red Hill Computing whom I often refer to in my research seem to really love this chip and claim it to be “vastly superior” to a 486DX-33 system though I would have to somewhat disagree. In a very optimized system the DLC can match or beat the DX-33 but I wouldn’t say it’s as fast clock for clock and I wouldn’t call a few frames per second advantage “vastly superior”. At the time though they would of been correct in that verbiage from a fiscal point of view as the DLC was vastly cheaper then a Intel 486DX-33 allowing the buyer to purchase more RAM.

I’m very curious how much the added cache of the later DLC chips such as the ones from TI and IBM affected performance and that may be the bases of an eventual revision to this article. The DLC does do what it claims to do and does increase performance of a 386 to 486 levels as well as being vastly cheaper then an Intel 486 but keep in mind it was still restricted by the 386 architecture and limited to the amount of RAM it could use. Possibly not a bad option for the budget user that already owned a 386 machine but holding out for the pricy 486DX-66 would of been a smarter move for the long run in my opinion.

Advertisements

386pic2

In this article we will be looking at what I consider the ideal setup for a 386 based PC. The 386 is the predecessor of the 486 CPU that we looked at in my Anatomy of a 486 DOS PC article. The CPU was produced from 1985 to 2007 but I think the heyday of this CPU and PC’s based around it is roughly from the late 80’s to early 90’s. The 386 is really the first CPU that was powerful enough to take full advantage of things like VGA and acceptably run games like Wolfenstein 3d. The golden age of DOS gaming lies with the 486 but it really started with the 386.

So why would you want to build a 386 based machine? Well that answer depends on you. Some people just consider it a cut down 486 and a somewhat uninteresting CPU. To a degree This is somewhat accurate and I myself would usually suggest a 486 or Pentium 1 over a 386 machine if you could only have one. So other then building an era correct machine for fun is there any practical reasons?

I would say yes though in all honestly like the Windows 3.1 based machine I covered earlier Putting a 386 together is more of a hobbiest pursuit then a mandatory build for classic PC gaming but I can provide two reasons.

1) sound options. This really only applies if you already have a 486. If you do you probably already have a sound blaster 16, maybe a midi card as well? multiple sound cards can be a pain to configure in DOS and some older sound blasters have been reported to have some mild speed issues with fast 486 machines and Pentiums. with a slower 386 you can experiment with different lesser known sound cards or if you went with the old stand by sound blaster 16 in your 486 you can mix it up and throw a older sound blaster or sound blaster pro in a 386 machine. Many games sound better on a SB or SB pro and the later SB pro cards tend to be less “noisy” cards then the later SB 16’s.

2) earlier games with speed issues. Probably the best reason to build a 386 machine. There is a limited era where games were coming out for 386 based PC’s and some of these games are rather CPU speed sensitive. The best known example of this is Wing Commander, a rather well known and beloved game that is terribly speed sensitive. Even a faster 386 or a slow 486 feels “off” with this game and a slower 386 around the 25mhz mark seems to be the sweet spot. Bubble Ghost and Test Drive III (as demonstrated via the 386 and 486 videos by LGR) are other games that come to mind that are very speed sensitive to faster 486 systems. With a faster 386 and a decent video card you can run games like Wolf3d extremely well and late EGA games just “feel right” on this machine.

Then again if your reading this page your probably a classic PC enthusiast and don’t really need much reasoning to put a classic build together. I know for a lot of people the 386 was their first real gaming PC so nostalgia can play an important roll in PC building. With that out of the way I’m going to commence detailing what I think is the ideal 386 machine and what I put together myself.

386alt

Here’s my 386 PC in a tower case. I try to use a case that captures the look of whatever era I’m going after and I think this tower suits the time. The 386 era seems to be when tower cases really started to come in vogue as opposed to desktop cases. I’m personally partial to desktops and that’s the form I used with my 486 build but I rather like the styling of the 386 era cases. There IS a style difference in my opinion though it may be subtle. In my opinion towers of the earlier era seemed to have more “flair” if that makes sense. With this case you can see it at the bottom with the large reset and turbo buttons (turbo button slows down the CPU BTW for compatibility with older games) and the extra big power button and then the grooved base. I think later cases starting around the 486 felt more utilitarian, boxy and plain with small buttons. It was still pretty common to find big power switches on the cases as opposed to press buttons as well.

So if we look at the case starting from the top we have my SCSI CD ROM drive. I believe mine is 12x speed. The CD drive is a bit of an extravagance for the era but definitely not unheard of. Having a CD drive installed makes things much more convenient especially for playing CD rereleases of games that came out at the time of the 386. Below that is a  standard 5 1/4 inch 1.2 MB floppy drive. Essential if you want to get the right look of the time for the 386. Also many games and applications were still being released on this format in the late 80’s early 90’s. in the smaller bays we have a standard 1.44MB floppy drive that gets a lot of use in this machine and below that is my SCSI Zip drive. I like to try to include a Zip drive in all my classic machines for convenience and definitely recommend adding one. Mine like in my 486 is the rarer SCSI variety since I went SCSI for this setup, which I’ll get into later. If your wondering why it looks so odd its because the only drive I had was a horribly ugly purple. Why Iomega decided to put out drives with purple face plates is beyond me and unfortunately I couldn’t just swap it with a white plate from a common IDE type drive thus I was forced to paint the face white. Trust me it still looks better then the original purple.

386alt2

Other then being very shiny the back is not to interesting. Were stuck with the AT keyboard and serial mouse again like on the 486 but that’s not a big deal. we have the standard parallel and serial ports along with the AT keyboard port and the multitude of expansion slots to the bottom.

Note in some of the images below the board is in an earlier case. I found the case above early on and transferred over to it but some images were already taken in the older case.

Operating System – For this machine I wanted to be a little different and more period correct so I have DOS 5.0 installed. I would suggest DOS 6.22 since its just a better OS but if you want to be more “correct” 5.0 is the one. There’s not to much difference except 6.22 is just a lot more user friendly but all games that run on 5 should run on 6 and vise versa. Besides it “installs in minutes” and of course “no PC should be without it!”

386os

Now to get into the guts of the machine, I’ll start with the motherboard and its components before we get into the expansion cards I recommend.

Motherboard – For the motherboard I went with a late era 386 board in order to get the best options for expandability. The board I used is a Chaintech 340SCD which uses the SIS “Rabbit” chipset which from my research and the prior owner of this board is one of the faster 386 chipsets.

386mb001

CHAINTECH-COMPUTER-COMPANY-LTD-386-325SCD-333SCD-3-1

Its a later board so it offers some feature not common on earlier 386 boards that I highly recommend having such as L2 cache and higher Ram limits which I’ll touch on in a moment. When dealing with 386 and earlier were limited to ISA expansion slots. My board has quite a few slots with two 8 bit and five 16 bit ISA slots. Luckily 16 bit slots were common place with the 386 so our expansion possibilities are wide and fairly cheap. Actually putting together a good 386 can be substantially cheaper then a 486 when you consider top of the line sound/video cards. Though keep in mind ISA is slower then VLB found on some 486 machines and of course later PCI slots. My board also has a pin for an external battery which is always desired to leaking barrel batteries.

3865

1) CPU – When talking about picking a CPU for a 386 board there is really only one CPU you should look at, the AMD DX-40, the greatest 386 and considered by many to be one of the greatest processors of all time. The DX-40 is a rock solid CPU that is both powerful and reliable. The DX-40 is very common so its not very expensive to acquire and it easily outperforms early 486 CPU’s. After all that praise I guess its odd to say that it is NOT the CPU I originally wanted for my 386. The answer to that is very simple though. Its simply to fast for what I was going for and If your running a DX-40 you may as well just run a 66mhz 486 which I already had. Fortunately at least on my board the CPU is speed adjustable via swapping the DIP-14 oscillator next to the CPU socket. By this method the CPU speed can be set to its rated 40mhz, 33mhz or my choice 25mhz. (speed of the CPU is half that of the oscillator so mine is 50mhz, originally 80mhz). Now if you don’t have a 486 and dont care so much about earlier DOS games then I would defiantly say keep the speed at 40mhz to allow you to play a multitude of games that stretch into the 486 era but if your like me and already have a 486 (or several in my case) then I think a slower 386 at 25mhz opens up a new earlier period of games and makes those earlier speed sensitive games playable with no fuss. After the fact I’ll say I do prefer the reliability and option to kick my speed back up to 33mhz or 40mhz with the DX-40 that I wouldn’t get with a standard 25mhz chip. I should also point out that CPU’s being soldered directly onto the motherboard was pretty common in this era as mine is. look for a socketed CPU motherboard if possible.

3866

Also of interest if you look slightly to the right of my CPU on the motherboard you will notice an empty socket. This for a Cyrix 486DLC chip. Basically it was a “upgrade” option as a 386 with 486 instructions and a very small amount of L1 cache on the chip. Its advantage over the on board DX-40 is debatable and its said to create stability issues on occasion. Best avoided and for my build purposes useless.

2) FPU math coprocessor – Unlike my 486 DX2-66mhz the AMD DX-40 (and as far as i recall) all 386 CPU’s have no built in math coprocessors to help with complex math calculations. This board though has a socket for the optional 387 math coprocessor. Mine came with a Cyrix x87DLC coprocessor installed. In reality though only a very small amount of applications and games take advantage of the 387. SimCity and Falcon come to mind, probably CAD programs if for some reason you feel the need to to do computer aided drafting on a 386.

3867

3) L2 cache – These are the sockets for the optional L2 cache or very fast memory the CPU can access for common tasks. Adding L2 cache like on a 486 board can dramatically help speed up your system. This is a feature to look out for even if your going for slower 25mhz or 33mhz machines. Many 386 boards seem to lack on board L2 cache. My board supports 256kb of cache which seems to be the max found on 386 boards. Since this image was taken I have fully upgraded my machine to 256kb of cache.

4) RAM – Again, since my board is a later model board it can support up to 32MB of RAM on 30-pin SIMMs which is massively overkill. I currently have my RAM at 16 MB which is still more then enough RAM and is more in line with the period. I do not know if there are any stability issues or game incompatibilities that may come up with large unexpected amounts of RAM such as 32MB on a 386. I would say its probably very unlikely and instances are few and far between but for stability and period correctness sake 16MB is enough. It lets me feel like I have a lot of wiggle room RAM wise while not being to ridiculous overkill. One could easily get by with 4MB for the intended games of the time. If though your going for a maxed out build or don’t have a 486 machine by all means 32MBs.

3864

5) Hard Drive – This is a 50 pin SCSI hard drive 2GB. I went with SCSI completely for this machine with the CD drive, Hard drive and Zip drive all being SCSI. using SCSI for my hard drive let me set up larger partitions easier and I think is a little faster then if I went IDE. The downside being 50 pin SCSI hard drives are nowhere near as common as the IDE variety.

6) Since most 386 boards, even my late model have very little built in your most likely going to require a 16 bit ISA I/O card for various things like serial and parallel ports. I’m just using a pretty generic controller here. It also had pins for IDE devices but since I went SCSI they are currently disabled. No drivers needed or anything. Its all set up by the jumpers. just plug it in and it should work.

3868

7) Video card – Like the 486 the Tseng Labs based cards are regarded as the DOS king in the 386 era as well. Unlike the 486 with its VLB slots we are limited again to 16 bit ISA. The card I’m using is the Tseng ET4000AX with 1MB of RAM. Widely regarded as one of the better if not best ISA DOS VGA card. Mine is a Cardex card but the manufacturer doesn’t make much difference. The ET4000AX offers vibrant colors and is fast as far as 16 bit ISA goes. Best of all they are relatively cheap and common, at least compared to their later VLB versions.

38610

8) SCSI card – This is my SCSI controller card I use to well, control my SCSI devices like my CD-ROM drive, Hard drive and Zip drive. I went with SCSI because I had the parts already and its a generally recommended option over IDE for a classic system. It supports more devices over IDE and is considered a little faster and more reliable with the downside being more expensive. I’m using an Adaptec AHA-1522A which is a little bit of an older card but unlike some SCSI cards it gave me no trouble to set up and also sports a floppy controller which I’m using to run my 5 1/4 and 3 1/3 floppy drives.

3869

9) Sound card – For sound card my recommendation once again goes to old sound stand by Creative. In this case in particular the Sound Blaster Pro 2.0 and its FM OPL3 chip. It will basically work with all games from the era that use FM synth and earlier and is of course adlib compatible. The card is noticeably better sounding then many of the early  Sound Baster 16’s is more period correct and many games of the 386 vintage sound better on it. No drivers are needed, simply add

SET BLASTER=A220 I7 D1 T4

to your Autoexec.bat via the EDIT command

38611

10) Midi card – I would say if you care about sound at all you want to add either a Roland or a 100% Roland compatible midi card. The 486 may of been a golden age for general midi but it got its start in the 386 era and many, many games can take advantage of the Roland MT-32 sound module for vastly better music. You could replace the above Sound Blaster Pro with a SB 16 for a crippled midi interface and noisier FM or you can use something like software emulation which I believe will allow you to use the SB pro’s game port as a midi interface at a cost of system performance but the absolute best route is to just get your hands on a midi card. I’m using a Music Quest MPU-401 Roland compatible card I grabbed off Ebay for a decent price. This is a known 100% compatible card but make sure you get one with firmware version 10 as earlier firmware versions are definitely known to have compatibility issues, especially with games from Origin such as Wing Commander. Also try to get one with a midi interface attached with it. Mine did not come with one so I’m using a hand made interface graciously made for me by a member at the Vogons forum whom I will leave unnamed since I’m unsure if he would want random people messaging him for cables in the future.

38612

In the end my 386 build was really fun to put together. It lacks the WOW factor of my 486 as far as cramming it with every possibly option but its a machine for a slightly simpler, yet not to archaic PC gaming era with less options but still a lot of power as well as character. You’ll notice like in just about all my builds I left out a network card of any sort. There is certainly a wide range of 16 bit ISA network cards you can find if you so choose but for me they just take space as I would never have a use for them. So is a 386 worth building? Its was certainly cheaper at least when compared to my monster high end 66mhz 486 with all the perks and trimmings. If you already have a reliable 486 I may say pass on a 386. On the other hard if your into retro PC building or want to experience games like Wing Commander on actual hardware I say put one together. A high or low end 386 shouldn’t break the bank.

*UPDATE*

I recently came across a old PC at a thrift store that has the exact “look” of the era I mentioned at the beginning of this article. Sure enough it sported a 386 inside but unfortunately the board was damaged beyond repair due to a battery leak. I did manage to eventually secure a smaller and possibly superior board that I replaced my old one with

I did replace the mother board with another smaller late era 386 board, the MS-3124 or Contaq-386.

COMPUTREND-SYSTEMS-INC-486-CONTAQ-386-MS-3124-1

This board has all the same abilities and features of the previous board that I want in a 386 plus is smaller and has a socketable 386 in case the CPU dies I can now actually replace it.

386alt3

386pic2 cpuHere is the original board that came in the case that was damaged beyond repair due to battery acid though its a little hard to tell from the Image. The board I replaced it with is identical in every way to this board with the exception of the chipset. My new one is SIS as opposed to the UMC chipset present on this board.

Benchmarks (AMD DX40 @ 25 mhz 386, 256 L2 Cache, 16MB FPM RAM, Tseng labs ET4000AX)

3DBENCH – 10.0

PCPBENCH – 2.5

DOOM -4.43

Quake – N/A

Speedsys – 4.19

I ❤ Old Games!

Retrogaming & other stuff

Waltorious Writes About Games

Game-related ramblings.

NekoJonez's Gaming Blog

A Journey Through A Gamer's Life

Old School Game Blog

Amiga enthusiasm, retro gaming passion

Evelynn Star

Lynn talks about video games, records and books ...

Retro Megabit

Sharing My Retro Video Game Collection.

133MHz's Junk Box

Random electronics and gaming crap

SNES A Day

Every game, every day

Too Many Games

A blog talking about games

Retrocosm's Vintage Computing, Tech & Scale RC Blog

Random mutterings on retro computing, old technology, some new, plus radio controlled scale modelling.

The PewPew Diaries.

Work(s) in Progress!

The Martian Oddity

Video Games and other weird stuff!

1001Up

1001 video games and beyond

retro computing and gaming plus a little more

sparcie

retro computers and stuff

jispylicious

Stay Jispy!

lazygamereviews

MS-DOS game reviews, retro ramblings and more...

%d bloggers like this: