Excellent, I don't need them but thanks on behalf of those that do. I'll add the phrase, FSB settings for Tyan S1437 in case that helps search engines drag ppl in the right direction.

Heh, lot of older boards with 16 and 20Mhz, I wonder if the AMD 386 sx/dx 40 peed on Intel's parade for selling many 486 at that speed.

There's also something funky with the way TH99 lists the S1437. There is an older product with the same name that is full AT size with an OPTi chipset, and then there is the one I have with the SiS chipset which is listed as "486VL EISA VESA LOCAL BUS (REV. 1.0)". It's definitely an S1437 though, because that's what is silk-screened onto the PCB. Strange that they list it as REV 1.o.

You might also want to make a note that the 512k and 1024k cache setting only works with the 400mil sockets. The board actually provides 32-pin 300mil sockets that seem to accept 128kx8 SRAMs, but for some strange reason the last two rows of pins are not connected...but you can bridge the pins to the 400mil sockets to make it work.

I have really really bizarre issues with the S1437 and it's keyboard controller. If the machine is not in v86 mode (running something like EMM386 or Windows) and I try to run SimCity 2000, the machine starts beeping via the PC Speaker and locks up. With EMM386 loaded (or another keyboard controller swapped in), it's fine.

Random question with regards to the Award BIOS from the AIR 486EI..... does it support APM? I know the AMIBIOS on the Tyan and NiCE boards is way too old to support it. I don't know if hardware support from the chipset is needed, but AIR advertised it as a feature on the 486EI regardless.

https://web.archive.org/web/19961029012651/ht … .com/486EI.html

IMO nothing actually supports APM... it sorta works, until the 17th (random number between 2 and 50) it goes to sleep then it wakes up with no video, or keyboard frozen etc.

I'd really like to get a hold of the Award BIOS from the 486EI motherboard that supports DX4. Are there any members that have the board?
The manual for the board is out there. I got the impression from reading it that the DX4 support is kind of a hack job.

DX4 CPUs work fine on the NiCE SuperEISA and Tyan S1437. I'm running a DX4-100OD on both. You aren't getting writeback L1 cache on them though as the chipset doesn't support it.

Oh, I realise they work, but the BIOS is not able to detect them properly because it's from 1992. I kind of doubt A.I.R. went the the trouble to update the BIOS for the 3.3V version of their board, though it would still be nice to try it. I think the guy with the Dolch PAC60 might have the 3.3V of the 486EI, but I can't contact him since I don't use twatter:

https://www.ckits.ca/blog/2018-12-19/128MB-in-486.html

So I went ahead and added 20k ohm pull up resistors to ADS#, LOCK# and SMI#, and disconnected all the NC pins. My board still can't boot the Cyrix 5x86 normally.

What if you use one of those cx5x86 Evergreen or other branded interposers intended to broaden platform compatibility?

I only have one evergreen interposer. It has many broken pins. It may be possible to salvage it, but it’ll be a big job.

*edit*
I looked in this. It has about 20 pins completely broken off. Replacing those is possible, but the by far the bigger issue is all the bent pins. I attempted to very carefully bend back two pins and they snapped off. So I would guess since pretty every pin is bent, by the time I tried to bend them all back I wouldn't have any pins left on the module.

Does anyone know how these modules are assembled at the factory. It looks like there are two PGA168 sockets soldered together with a PCB in between, but I have no idea how the hell they managed to solder it.

I just tested two additional BIOSes on my board.
-Dolch PAC60 uses an OEM version of A.I.R. 486EI AMIBIOS. Seems to be from PCB revision 1.5x, and doesn't have support for DX4.
-Abit AE4 uses Award Modular BIOS v4.20. Amazingly this one will properly detect the 1MB cache on my board, but only 32MB of DRAM.

Neither of these BIOSes help the Cyrix 5x86 situation.

How much cache is detected with your original BIOS and does all of it work properly, or just what the BIOS sees works?

All of the cache (1024kb) is detected by the original BIOS. All jumpers are set correctly, and the cache works properly.

The Award v4.50pG BIOS does not detect the cache and it does not function.
Award v4.20 detects the cache and it works properly. Only this BIOS doesn't support 16MB 30-pin SIMMs.
The v4.50 is from Asus 486SV1. Maybe there's something special about the way cache is wired up on that board?

I picked up one of these the other day. The guy had about 15 of them for sale on eBay but the are all gone now.
The package reads it supports 486dx4-100 and AMD 5x86-133.
I haven’t tried it yet. Its going in my IBM PS/1 which has an Overdrive socket that only supports 169-pin CPUs.

Intel486dx33 wrote on 2021-09-05, 19:54:

I picked up one of these the other day. The guy had about 15 of them for sale on eBay but the are all gone now.
The package reads it supports 486dx4-100 and AMD 5x86-133.
I haven’t tried it yet. Its going in my IBM PS/1 which has an Overdrive socket that only supports 169-pin CPUs.

This is really off-topic. Why did you decide to post this here and at this time?

Anonymous Coward wrote on 2021-09-04, 09:58:

I just tested two additional BIOSes on my board. -Dolch PAC60 uses an OEM version of A.I.R. 486EI AMIBIOS. Seems to be from PCB […]
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I just tested two additional BIOSes on my board.
-Dolch PAC60 uses an OEM version of A.I.R. 486EI AMIBIOS. Seems to be from PCB revision 1.5x, and doesn't have support for DX4.
-Abit AE4 uses Award Modular BIOS v4.20. Amazingly this one will properly detect the 1MB cache on my board, but only 32MB of DRAM.

Neither of these BIOSes help the Cyrix 5x86 situation.

Sorry for bringing this one up ... you got some info on the cache mod you made on the Abit board AE4? And the EISA CFG file for the board?
Thanks :)

/Eirik

I did a modification on a Tyan S1437. I don't own an Abit AE4, I just tested the AE4 BIOS on my SuperEISA and S1437.