Fastest AT-board (without mods): https://theretroweb.com/motherboards/s/acorp-6via85t

Thanks! I'll be looking for this one.

There are some PGA478 Baby AT boards. Taiwan Commate/Commel P4XB (fastest to have AT power connectors) and APC Phoenix AT actually are in theretroweb.com database but I haven't found any others. There's also the APC Gator AT, which is a PGA479 board with ISA and PCI slots but no AGP slot.

These look pretty good if you don’t need ISA

https://theretroweb.com/motherboards/?page=1& … =5&platform1=27

I might get around to kinda fast, 440BX AT board I've got, last time I couldn't get anything faster than PII-450 going, but I have a lin-lin adapter and expanded collection of slotkets now. Doesn't go real high on the bus though, only 115. https://theretroweb.com/motherboards/s/pcpart … bxb847d-35-8847

douglar wrote on 2024-10-01, 22:38:

These look pretty good if you don’t need ISA

https://theretroweb.com/motherboards/?page=1& … =5&platform1=27

The fastest and somewhat rare and buggy were the Socket A SIS boards that PCCHIPS marketed. M812lmr and similar.

If memory serves you could get 1.4ghz working officially and up to 1.8ghz (unofficially) if you found a low power laptop chip.

Sadly these boards were rare/expensive in most of the us and were only abundant in certain overseas countries.

Anything beyond Socket 370 and super rare Socket A motherboards is going to be industrial motherboard territory. It may be worth it to look into industrial motherboards and AT form factor backplanes. Usually these are expensive, but sometimes you can get lucky.

Another thread on this subject: Most recent platform for Baby AT motherboards?

douglar wrote on 2024-10-01, 22:38:

These look pretty good if you don’t need ISA

https://theretroweb.com/motherboards/?page=1& … =5&platform1=27

The APC Phoenix AT has 2 separate ISA slots and one ISA/PCI combo slot.

rmay635703 wrote on 2024-10-01, 23:50:

The fastest and somewhat rare and buggy were the Socket A SIS boards that PCCHIPS marketed. M812lmr and similar. […]
Show full quote

douglar wrote on 2024-10-01, 22:38:

These look pretty good if you don’t need ISA

https://theretroweb.com/motherboards/?page=1& … =5&platform1=27

The fastest and somewhat rare and buggy were the Socket A SIS boards that PCCHIPS marketed. M812lmr and similar.

If memory serves you could get 1.4ghz working officially and up to 1.8ghz (unofficially) if you found a low power laptop chip.

Sadly these boards were rare/expensive in most of the us and were only abundant in certain overseas countries.

Jetway and Zida also made some.
https://theretroweb.com/motherboards/?page=1& … 5&cpuSocket1=17

But it seems like the fastest Socket 478 CPU (3,4 Ghz Pentium 4) was a bit faster than the fastest Athlon XP (3200+).

akimmet wrote on 2024-10-02, 00:32:

Anything beyond Socket 370 and super rare Socket A motherboards is going to be industrial motherboard territory. It may be worth it to look into industrial motherboards and AT form factor backplanes. Usually these are expensive, but sometimes you can get lucky.

The APC/Corvalent ones seems to be insustrial based on the amount of ISA slots.

Kvopper256 wrote on 2024-10-02, 12:59:

douglar wrote on 2024-10-01, 22:38:

These look pretty good if you don’t need ISA

https://theretroweb.com/motherboards/?page=1& … =5&platform1=27

The APC Phoenix AT has 2 separate ISA slots and one ISA/PCI combo slot.

I see that, but it looks like they are attached with a bridge chip attached to the PCI bus.

I don't know for sure about this particular implementation, but usually slots like that lack some ISA features like DMA.

No DMA means that ISA sound cards might not work as expected in DOS.

PICMG would be the way to go, backplanes with Single Board Computers.

The backplanes are AT by default (usualy baby AT, but full AT also exists), the SBCs can have anything from a 486 to contemporary CPUs.

PICMG 1.0 offers PCI and ISA PICMG 1.2 32b and 64b PCI, PICMG 1.3 gives you PCI and PCI-E. With the latter you could get a 2020s era CPU and GPU in an AT case. Only thing to watch is BIOS vs UEFI support of the SBC. Can't tell you anything from experience there as I'm firmly PICMG 1.0 with P1, P3 and P4 boards, which is old BIOS stuff.

In recent years I have built few AT based machines with soc370 or Slot1 boards. Namely Zida ZX98CU (soc370, works with Coppermines out of the box, can be modified for Tualatin but it refused to POST at 133 MHz despite everything) and Acorp 6ZX86 (slot 1). Equipped the latter with 2x256 MB RAM, MSI Ti4200 128 MB and Tualatin 1.26 GHz with modified adapter, works nicely. With 200watt AT power supply it occasionally froze, with ATX it and its stronger 3.3v it works nice and stable.

Paadam wrote on 2024-10-02, 18:12:

In recent years I have built few AT based machines with soc370 or Slot1 boards. Namely Zida ZX98CU (soc370, works with Coppermines out of the box, can be modified for Tualatin but it refused to POST at 133 MHz despite everything) and Acorp 6ZX86 (slot 1). Equipped the latter with 2x256 MB RAM, MSI Ti4200 128 MB and Tualatin 1.26 GHz with modified adapter, works nicely. With 200watt AT power supply it occasionally froze, with ATX it and its stronger 3.3v it works nice and stable.

You should try using a 300W AT PSU like the NOS Topower that I saw recently on eBay.

Kvopper256 wrote on 2024-10-02, 13:03:

Jetway and Zida also made some. https://theretroweb.com/motherboards/?page=1& … 5&cpuSocket1=17 […]
Show full quote

rmay635703 wrote on 2024-10-01, 23:50:

The fastest and somewhat rare and buggy were the Socket A SIS boards that PCCHIPS marketed. M812lmr and similar. […]
Show full quote

douglar wrote on 2024-10-01, 22:38:

These look pretty good if you don’t need ISA

https://theretroweb.com/motherboards/?page=1& … =5&platform1=27

The fastest and somewhat rare and buggy were the Socket A SIS boards that PCCHIPS marketed. M812lmr and similar.

If memory serves you could get 1.4ghz working officially and up to 1.8ghz (unofficially) if you found a low power laptop chip.

Sadly these boards were rare/expensive in most of the us and were only abundant in certain overseas countries.

Jetway and Zida also made some.
https://theretroweb.com/motherboards/?page=1& … 5&cpuSocket1=17

But it seems like the fastest Socket 478 CPU (3,4 Ghz Pentium 4) was a bit faster than the fastest Athlon XP (3200+).

Only if it works, most of my AT Midtowers had 250 watt PSUs which is fine for most durons and celerons.

Push clock speeds and things get unstable due to inadequate power delivery

rmay635703 wrote on 2024-10-04, 20:48:

Kvopper256 wrote on 2024-10-02, 13:03:

Jetway and Zida also made some. https://theretroweb.com/motherboards/?page=1& … 5&cpuSocket1=17 […]
Show full quote

rmay635703 wrote on 2024-10-01, 23:50:

The fastest and somewhat rare and buggy were the Socket A SIS boards that PCCHIPS marketed. M812lmr and similar.

If memory serves you could get 1.4ghz working officially and up to 1.8ghz (unofficially) if you found a low power laptop chip.

Sadly these boards were rare/expensive in most of the us and were only abundant in certain overseas countries.

Jetway and Zida also made some.
https://theretroweb.com/motherboards/?page=1& … 5&cpuSocket1=17

But it seems like the fastest Socket 478 CPU (3,4 Ghz Pentium 4) was a bit faster than the fastest Athlon XP (3200+).

Only if it works, most of my AT Midtowers had 250 watt PSUs which is fine for most durons and celerons.

Push clock speeds and things get unstable due to inadequate power delivery

There's a NOS 300W Topower on eBay right now https://www.ebay.com/itm/304466714614 and the Topower website mentions this 400W PSU http://topower.com/product/at_400ssce.html The Athena Power brand new ones are rated for 300W and 400W but the quality is very poor.

Paadam wrote on 2024-10-02, 18:12:

In recent years I have built few AT based machines with soc370 or Slot1 boards. Namely Zida ZX98CU (soc370, works with Coppermines out of the box, can be modified for Tualatin but it refused to POST at 133 MHz despite everything) and Acorp 6ZX86 (slot 1). Equipped the latter with 2x256 MB RAM, MSI Ti4200 128 MB and Tualatin 1.26 GHz with modified adapter, works nicely. With 200watt AT power supply it occasionally froze, with ATX it and its stronger 3.3v it works nice and stable.

Im building now a PC with a Zida BX3D-CT, i think is just a ZX98CU with integrated sound card, is a VERY GOOD card, wide range of cpu, stable, and bios is pretty easy to patch for 128GB HDD

About 18 years ago I picked up an Epox V370B baby AT Socket 370 board; the plan was to use it to make a decent computer to give to a friend's daughter since I had a number of AT cases on hand. I bought a Lin Lin adapter (inexpensive at the time) and to my surprise it worked fine with a 1.4 Tualatin Celeron (might have been a 1.2). I was even able to overclock it a bit, but with no CPU voltage adjustment I couldn't get very far. That's the fastest AT computer I've personally ever had.