For DOS / Windows and a 3dfx PC, i would say a AMD K6-2 (+) or K6-3 (+) would be a good choice. Cause with cache disable tricks, you can run really good old DOS games. Only for late Win98 things you need something else.

There are several SS7 boards available, but i don't know if there is any micro board out there ....

I've tested this mainboard several weeks ago... It has some of your requirements, but can take only the mendochino Celerons. For flexibility the K6 familiy is much better.

http://www.cbo-do.de/Mainboards/Intel/Intel-S … -RAM::2597.html

I've not tested, but i think the Athons (T-Bird or newer) are not good for these cache tricks. Should be the same like the Pentium 3, i have tested with disable the L1/2 cache.

Maybe a BCM IN5598? I thought about doing a build based on that, but decided to search for parts to upgrade my current one.

I agree with getting a amd k6 3 processor, which means youll need a super socket 7 motherboard. There are ATX style boards but all that I personally know have 6 or 7 slots. Ill see if I cant hunt down a smaller one.

Amptron / Eurone PM-599LMR

ASUS SPAX-M

Those are the two smallest I can find. The asus MAY fit into a BTX style itx case

I'd also go for a K6-2+ or K6-3. There are many AT boards that have all the conectivity you want, plus ATX power connectors to use a modern power supply. Whereas AT cases may be a bit tricky to find today, they usually have small dimmensions and definitely have that retro feeling 😀

I was thinking Thunderbird because with the pencil trick you can unlock the multiplier and undervolt/underclock to 100Mhz FSB and maybe get a 2x multiplier.

With cache disabled, it might hit a "fast 486" speed, or Pentium 75 level, which would be sufficient for my needs.

Not looking to play 386 level stuff, I have an actual 386 for that.

DNSDies wrote:

I was thinking Thunderbird because with the pencil trick you can unlock the multiplier and undervolt/underclock to 100Mhz FSB and maybe get a 2x multiplier.

With cache disabled, it might hit a "fast 486" speed, or Pentium 75 level, which would be sufficient for my needs.

Not looking to play 386 level stuff, I have an actual 386 for that.

the PC Chips MB741LMRT is a slot 1 board with a p3 slot as well. 1 isa and 1 pci

Maybe this will work for you then. http://www.ebay.com/itm/PC-COMPUTER-DOS-WINDO … N-/271954986955

Celerons are multiplier locked, but that's similar to what I want.

My build's case will be custom-made though, with flexible cable risers for the ISA and PCI slots so they can be put in horizontally facing opposite directions.

I'll also have a slim DVD drive, 250W flex ATX power supply, and a single 120MM slim case fan above the processor to serve as exhaust.

It shouldn't be more than 4 or 4.5 inches in height, and maybe 10x11 inches wide and deep, depending on the size of the motherboard.

DNSDies wrote:

Celerons are multiplier locked, but that's similar to what I want. […]
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Celerons are multiplier locked, but that's similar to what I want.

My build's case will be custom-made though, with flexible cable risers for the ISA and PCI slots so they can be put in horizontally facing opposite directions.

I'll also have a slim DVD drive, 250W flex ATX power supply, and a single 120MM slim case fan above the processor to serve as exhaust.

It shouldn't be more than 4 or 4.5 inches in height, and maybe 10x11 inches wide and deep, depending on the size of the motherboard.

I just edited my post for the below board, should be what you need, minus mulitplier stuff. Im still looking as Ive thought about it but never invested time into searching

PC Chips MB741LMRT

I did it. Found it. Yay.

http://www.motherboard.cz/mb/chaintech/CT-7AIA.htm

https://www.cnet.com/products/chaintech-7aiv- … socket-a-kt133/
http://m.okidoki.ee/item/5219306/

matx k7 amd with agp, pci, isa. Two different revisions of the board. The ONLY board I found with it out of maybe almost 300 matx boards, Nothing smaller. No amd socket after this one has a chipset that supports isa. previous would be socket 7. So this board is your literal only option.

Good luck finding it for sale, as im going to be looking for one too now 🤣

DNSDies wrote:

I was thinking Thunderbird because with the pencil trick you can unlock the multiplier and undervolt/underclock to 100Mhz FSB and maybe get a 2x multiplier.

With cache disabled, it might hit a "fast 486" speed, or Pentium 75 level, which would be sufficient for my needs.

Not looking to play 386 level stuff, I have an actual 386 for that.

I had a look onto the manual of the board you mentioned. The Shuttle MK20. The manual has version 1.0.
You have mentioned also the revision 1.2, but i don't think that the result from the following is really different to Rev. 1.0

The Shuttle MK20 has a Via KLE chipset.
http://www.motherboard.cz/mb/shuttle/MK20.htm

The BIOS is from AWARD, and what you can see in the manual is that you cannot change any multiplier in the BIOS. Compared to SS7 boards you also have no jumpers onboard.
Even when you go for the pencil trick you have no chance for multiplier change.

The only way is maybe, to flash an alternative BIOS if available and with the settings you need.
Or maybe a hardware PIN-mod, if possible for T-Birds... Don't know if the 2x would be available you mentioned. Mainly the first multipliers for Via's KTxxx mainboards will be 5.0 and higher.

A Comparison of my K6-2 and a PIII from me to estimate the different speed when caches disabled (example with PCP Bench):

PIII 866MHz, 133FSB - (cache on) - 162.9
PIII 650MHz, 100FSB - (cache on) - 136.1
PIII 433MHz, 66FSB - (cache on) - 105.9
PIII 433MHz, 66FSB - (cache off) - 1.4

K6-2, 500MHz, 100FSB - (cache on) - 118.3
K6-2, 500MHz, 100FSB - (L2 off) - 88.9
K6-2, 500MHz, 100FSB - (L1 off) - 10.9
K6-2, 500MHz, 100FSB - (L1+L2 off) - 3.5

K6-2, 166MHz, 66FSB - (cache on) - 55.3
K6-2, 166MHz, 66FSB - (L2 off) - 47.3
K6-2, 166MHz, 66FSB - (L1 off) - 6.7
K6-2, 166MHz, 66FSB - (L1+L2 off) - 2.6

From the tests i've seen, the values from the database (see next link) and what is explained here on vogons, you cannot go from 386 to 486 to Pentium speed with your Athlon...

A good overview of different speeds is here:
Let's benchmark our systems with caches disabled

For SS7, look for a FIC VA-503+. While not quite as tiny as you want, it's pretty small nonetheless. HAs 3ISA, 3PCI and AGP, takes 72-pin and 184-pin memory, has both AT and ATX power connectors and works with K6/2 and K6/3 up to 550MHz. I have one, it's pretty nifty. And it's less uncommon to find on sale than dragon teeth.

Hello, it looks like I've already done something like you would like to build 😀 i used PC Partner MVP3BS7-954 mainboard or something similar (the mainboard doesn't have any information printed on it), which is only a little wider than ISA slots, and I made a custom AT case with turbo button, slim CD-rom, floppy drive and 2,5" hdd for it. It has K6-2 (will be replaced with K6-2+) and Voodoo Banshee. I decided to create a very small tower, not a desktop-style case, because you can put such tower-style case on the desk and it will be taller than a desktop-type, but will take actually less space because it is much thinner. My case is only as thick as it is needed to hold the slim CD-rom, but it can use regular PCI/ISA/AGP extension cards without any risers.

Here is a topic with more information about my project: Miniature SS7 K6-2 + Voodoo Banshee PC

So, if you are looking for a small Socket 7 mainboard, check the MVP3BS7-954 😉

And I recommend building a small, vertical tower and putting it right next to the monitor, in my opinion it can be a better solution than a desktop-style case.

Using the web archive, I noticed that Chaintech's BIOS updates mention new clock multipliers.

http://web.archive.org/web/20040824084716/htt … MBDL.htm#DRIVER

Another option may be going with a PII or P3. I understand some of those can be underclocked easily enough.

As far as a Super Socket 7, I have a P5AB motherboard and a 550mhz AMD K6-3 CPU for it.
I could always adapt it for this project, but I wanted something with a little more maximum speed.

adalbert wrote:

http://www.vogons.org/download/file.php?id=27454&t=1 […]
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Floppy at the bottom, that's original. May be a little hard to change disks though.

stamasd wrote:

May be a little hard to change disks though.

Well, you are not the first to say that, but I really don't know why people think so 😀 the floppy drive is the heaviest element of that case and it provides proper center of mass. Of course, it might be more difficult to change disks if it sits on the floor, but keep in mind that it is intended to be used on the desk.

adalbert wrote:

So, if you are looking for a small Socket 7 mainboard, check the MVP3BS7-954 ;) […]
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So, if you are looking for a small Socket 7 mainboard, check the MVP3BS7-954 😉

And I recommend building a small, vertical tower and putting it right next to the monitor, in my opinion it can be a better solution than a desktop-style case.

Well, the jumpers look like you have to set and forget them, but the CPU socket placement is 100% right. It'll be usable with full length ISA and PCI cards. Nice!