No, there's no cache on the board. I'm pretty sure cache wasn't standard on 386 boards, many boards lacked it. This is not en high-end board either anyway.

I agree to what derSammler says. Also, caches weren't that popular until about the 90s, when 386DX-33 or -40 processors became common.
Apart from professional equipment, of course. CAD/CAM, etc. If you're lucky, you can find a 486DLC chip for cheap.

It has a little on-chip cache and supports I486 instructions. If the mainboards isn't using an oddball design, it should work with it.
Just remember to load a little DOS driver that enables that cache..

Considering the fact, that a DX40 barely runs Doom playable (low res, low detail) you should probably adjust your expectations on what your DX25 can achieve in Doom, especially when it comes to high detail and full res.

64kb of cache in a 386 was high. The A series of IBM model 80's got this treatment. From ZERO to 64kb. From IBM. Cache ram was EXPENSIVE AS FUDGE back 'in the day'. Don't expect cache on a 386 until 33 & 40 mhz. Even then, don't expect a lot of it.

blurks wrote:

Considering the fact, that a DX40 barely runs Doom playable (low res, low detail) you should probably adjust your expectations on what your DX25 can achieve in Doom, especially when it comes to high detail and full res.

Well, I'm expecting more than 1.1 FPS to be honest. I only got 4.6 FPS on the lowest detail in the tiniest window possible, and the graphics glitched out halfway through.

Anyway it's not just Doom, other stuff seems unusually slow and flaky too while some things (e.g. Crystal Dream II by Triton) run about as well as you'd expect. I'm suspecting something might actually be wrong.

Yeah that's unusual. My SX 25 does better than this I think (I did not bench it but that's how the game feels)

However my 386SX25 is well optimized (with 70NS RAM, a good video card, tight ram timings ...). Check that on yours to get more performance

xjas wrote:

blurks wrote:

Considering the fact, that a DX40 barely runs Doom playable (low res, low detail) you should probably adjust your expectations on what your DX25 can achieve in Doom, especially when it comes to high detail and full res.

Well, I'm expecting more than 1.1 FPS to be honest. I only got 4.6 FPS on the lowest detail in the tiniest window possible, and the graphics glitched out halfway through.

Anyway it's not just Doom, other stuff seems unusually slow and flaky too while some things (e.g. Crystal Dream II by Triton) run about as well as you'd expect. I'm suspecting something might actually be wrong.

thats pretty slow indeed, i got 8.5fps with 386dx-40 and default settings. 😀

xjas wrote:

[Anyway it's not just Doom, other stuff seems unusually slow and flaky too while some things
(e.g. Crystal Dream II by Triton) run about as well as you'd expect. I'm suspecting something might actually be wrong.

Hmm.. Maybe the system has wait states or turbo-button enabled, don't know. Sorry. 🙁

DOOM relies on a fast VGA card, your Trident will not run DOOM faster, no matter how much power the CPU would have.

^^ I would have thought it'd be CPU limited due to geometry calculation, etc. The Trident card is an 8900cl (although DIAG identifies it as a 9000 for some reason) and configured for 0 WS memory, but I actually think that it's overdriving the VRAM as I get graphical glitches in some stuff. (I didn't set it up.) I also get a lot of slowdown in SOME games - notably Jazz Jackrabbit & Vinyl Goddess - with a lot of sprites on-screen when they scroll vertically. I have an ET4000 on order, so I'll see how that performs when it gets here. (And yes, I KNOW the ET4000 has problems with some scrolling games.)

Anyway here are my mainboard swap options; I don’t actually know what either of these are or much about them. If anyone knows what they are please post it! I thought the one on the left was made by MSI but I think that’s an inventory code or something.

The left one has a DX/40 already fitted, 128kB cache (upgradable) and appears to be a 386/486 selectable board?? with these little jumper blocks all over to configure it. It has two Contaq(?) chips and one SiS. Unfortunately it’s missing the keyboard controller and the BIOS. Also my FasMath is a 33MHz part (despite being currently paired with a 25MHz CPU), not sure if I could overclock it to run at 40.

(Note that I left some of these pics HUGE so you can zoom in & read stuff.)

(More pics of the left board due to the forum's attachment limit)

The board on the right is, to borrow Phil's phrase, quite frankly gorgeous. 😜 It’s this deep coffee color which doesn't come across in the pics, with striking gold PCB traces in a mostly-planar vertical layout. It seriously looks like ‘80s cyberpunk art. Or I’m just a dork.

It seems to have a full compliment of cache and two parity(??) chips that are shorter than the sockets they’re in. Unfortunately it has a Dallas RTC, which is almost certainly dead & annoys me, and it’s also missing the keyboard controller and the BIOS and the main oscillator, although I could always harvest the current one from the DX25 when I swap the CPU & FPU. The only silkscreened marking on it that might be a model # says REV:A3 386SC.

No idea if either of these work because of the missing chips. How standard are the keyboard controllers? I’m guessing I can’t just swap the BIOS over but I do have an EPROM burner so I could roll my own if I had an image and knew what kind of chip it needed.

Anyone know what either of these are? I’d love to have manuals with jumper settings, etc.

i used to own one of those contaq boards. Solid board. search these forums for '386 contaq'. there should be a lengthy thread about them.

replacing the bios is super easy. keyboard chip slightly harder. just get the needed part number from images and wait on ebay or salvage it from another board.

luckybob wrote:

keyboard chip slightly harder.

Why do you think? Any 8042 from some other mainboard should work.

Looking at your first post, I noticed that you were mixing RAM chips of different density, e.g. bank0 has 9-chip, while bank1 has 3-chip. Is this allowed by the chipset, or just something that people tend to avoid doing? I've never mixed chip densities like this myself on a 386.

Cache wasn't that common on 386SX boards. It was less common to have cache sockets missing from 386DX boards, especially the 33/40 MHz variants.

You mentioned that you have an MSI 386 board? Which board in particular? I have an MSI 386 board. Not too much of an issue to source KBCs. If it uses the UMC 481/482, there is a nice MR BIOS for that chipset online.

How are you getting free boards from the university? Do you work their IT, or are you a student there? Back when I was a student, they would leave the recycleable computer items in the hallway with a note saying 'take all you want'. But apart from my student days, I don't have anybody to send me a line when there are computer parts in the hallway.

Jo22: some motherboards have a hardware flush circuit and do not need the DOS driver to use the 486DLC. He mentioned an MSI board at one point. If it is the MS-3131, it has the hardware flush circuit. When combined with MR BIOS, it is a pretty fast board. With the right combination of hardware, you might get 15 fps from DOOM.

xjas: A Trident 8900D should be fairly quick in DOOM, but not the 8900CL. I would remove that cacheless motherboard from the case. I mean... "Solutions" is the brand of the chipset?

I like the look of that MSI board, but I don't think its a MS-3131. It might say if you remove that white sticker. At least that is the location where my MSI board would say "MS-3131", so I'm assuming your MSI board has the model in a similar location. Everything else about the look of the board is similar to my MSI board, like that yellow sticker and the general appearance, Not to mention it says MSI on that grey sticker just as mine does.

I'm not sure of the Contaq brand as a chipset. Ask user Anonymous Coward.

I've never seen silk screened works 386, 486 as selectable by a resistor pack. Looks interesting though.

It probably can use any of the standard pinouts for KBC's of the time, so I wouldn't worry about that. Try to look for a BIOS which works with generic Contaq 591/592 boards. With any luck, there will be a MR BIOS. I like how all the components on this board are tidy, even the DRAM sockets, unlike that unsightly DRAM SIMM offset on your "gorgeous" board.

If I recall correctly, the Symphony chipset was supposed to be pretty decent. Look for MR BIOS for Symphony 362/461. The presence of the Dallas probably saved the board for a battery acid death. Dallas chips are easy enough to remove and to place a socket in their place.

Whoever was getting rid of these boards, not knowing what they were doing, probably thought that the BIOS and keyboard controller chip contained "sensitive information" about their system, so they got rid of the chips.

Thanks for all the input all, isn't deciphering mystery boards fun?

Fairly sure this is the Contaq/SiS board: http://stason.org/TULARC/pc/motherboards/C/CO … 86-MS-3124.html - useful to know.

derSammler wrote:

luckybob wrote:

keyboard chip slightly harder.

Why do you think? Any 8042 from some other mainboard should work.

feipoa wrote:

It probably can use any of the standard pinouts for KBC's of the time, so I wouldn't worry about that.

This was the answer I was hoping for to be honest. Sounds like I can probably pull the KBC from the cacheless board and try it in either of these? I hate to sacrifice a known-working board to a questionable one though. Is there any chance I could damage something if the chip/pinout is wrong?

feipoa wrote:

Looking at your first post, I noticed that you were mixing RAM chips of different density, e.g. bank0 has 9-chip, while bank1 has 3-chip. Is this allowed by the chipset, or just something that people tend to avoid doing? I've never mixed chip densities like this myself on a 386.

Didn't think that would be any issue, I got it that way.

feipoa wrote:

You mentioned that you have an MSI 386 board? Which board in particular? I have an MSI 386 board. Not too much of an issue to source KBCs. If it uses the UMC 481/482, there is a nice MR BIOS for that chipset online.

I now think it's the board linked to at the top of this post (MS-3124.)

feipoa wrote:

xjas: A Trident 8900D should be fairly quick in DOOM, but not the 8900CL. I would remove that cacheless motherboard from the case. I mean... "Solutions" is the brand of the chipset?

Well, it has at least a partly-UMC chipset... but yeah those "Solutions" chips sound kinda dodgy to me too.

feipoa wrote:

Whoever was getting rid of these boards, not knowing what they were doing, probably thought that the BIOS and keyboard controller chip contained "sensitive information" about their system, so they got rid of the chips.

I think they harvested them for EPROMs, both these came out of a box of spare parts for a machine shop so I imagine they knew exactly what they're doing. (Keyboard controllers seem to have a stickers on them a lot of the time making them look like EPROMs??)

As far as I know, there weren't EEPROM's available for BIOSes in 1990-1992. They were usually one-time programmable, or UV-erasable. Perhaps whoever nabbed them had a UV eraser. Its possible that somebody wanted backup keyboard controller chips. I've swapped around various brands of 8042 keyboard controllers among motherboards without incident. Even those which contain the controller for a PS/2 mouse seemed to work in boards not intending use for a PS/2 mouse. If you are concerned, at least make sure that the locations of Vcc and GND on the donor DIP-40 are the same as on the receiver DIP-40.

Start looking around for the contaq and symphony BIOSes. There are a few sites on the net like this,
http://sannata.ru/bios/386DX/
Look for SYM461.ZIP . this may BIOS will probably work with your Symphony board.

A lot of these later 386 boards contained chipsets which worked with, both, 386 CPUs and early 486 CPus, in which case you can look in,
http://sannata.ru/bios/486/
Perhaps CON486_1.ZIP ? When I open the zip file, though, there is a doc which says 82C546, so probably not for your 591/592 Contaq chipset.

There are other sites with larger repositories. Sorry, I don't bookmark things anymore because I can never remember how to access my bookmarks with these modern browsers.

EDIT: Found some of my old posts,
Try:
http://chukaev.ru54.com/bios_en.htm
e.g. 3sym001.zip for the Symphony

http://files.mpoli.fi/hardware/ROM/MRBIOS/ and its parent directories

You may also want to contact the poster of this thread, lazibayer, Notes on Contaq-386/MS-3124
He seems to have the MS-3124 and its BIOS. If he can image it, you can put it onto an EEPROM.

EDIT: Already looked at the oldest MSI website on wayback, but the oldest board BIOSes they have on there are for socket 3, 486.
https://web.archive.org/web/19970329193700/ht … .msi.com.tw:80/

Isnt the trident 8900cl more suitable to a 286 system?