Pretty sure they are all industrial boards. In any case they are expensive as heck.

Be careful with that p4 and a voodoo3 agp, i don`t think that board supports 3,3v agp...

^
Another issue. The integrated Video might have 9x drivers (if there is any)

My favorite system is the one based on the p5a, it does everything great. I have multiple ss7 boards but i simply love the Asus. You indeed do need the 1.03 or 1.04 for the + cpu`s but the 1.06 works fine with a normal k6-3 450mhz (i have all three boards).

Agp is no issue with mine: only tnt2 cards are unstable but voodoo3, matrox g200 and geforce2GTS and Ti work flawless (just use the 1.70 agp driver from ali).
I had more trouble with boards based on the mvp3 chipset than with the Ali ones.

With voodoo3 (or v2 sli) at 1024x768 and a k6-2+@550 there is just a very small bottleneck but works very nice. For games at 800x600 and lower a p3 is way faster (even a p2-450 is).

I also have a jetway 542B and 542C and the 542B is also a very stable and fast board with the k6-2+, only downside (for me) is it is not atx but does support atx psu. The 542C is a bit slower and the ``feel`` of the 542B was better. Maybe you can find one of these.

If you want a via mvp3 based board: my experience is the best with an Aopen ax59pro.

Back in the day I had a FIC VA503+ with K6-3+, it was a really nice AT MVP3 board. However, I really question the usefulness of AGP on Socket 7. The stability problems with anything non-3dfx are well known, and a PCI Voodoo3 performs nearly as well as the AGP version. PCI Voodoo3 aren't that common, so Voodoo2 SLI is an alternative.

Intel Triton 2 (HX/VX/TX) on the other hand is rock solid and there are boards that will support SDRAM, K6-3+ and stable 75Mhz bus. The cacheable limits aren't an issue with the K6+ CPUs. Memory bandwidth is probably a bit down on Super 7. Asus TXP4 is the one I use, there is an ATX version TXP4-X too.

Just throwing another option in there 😎

Agp issues all come from the early days in my opinion because neither ali or via had a stable driver for it (and it took them way too long). Nvidia was to blame also, their drivers improved stability also.

Later driver revisions worked much better but the word was out that they didn`t work stable with agp cards and people keep on copying that today (imho)... A bit like Vista, nobody wants it and it is every bit as stable and functional as windows 7 today, early driver and support problems kept it from getting popular.

I do agree about the voodoo part and actual usefulness of the agp slot. 3dfx cards speedwise work best and pci versions are just as fast.

I like the ss7 a lot and to me it is the ultimate retro allrounder. I have a system from about every era but the ss7 is what i use the most.

And it just might be pure coinsidence but every time i did build a retro pc through the years and it wasn`t stable (lockups, bluescreens), it almost always was an AT board. I now use atx boards only and have FAR less issues with win98se.
I hated dell, compaq, HP systems back in the day (for obvious reasons) but they were stable and they adopted the atx layout way earlier. But i could be just me 🤣

Well PIII Wise I have an INTEL E139761 and a Jetway j-993as-l motherboard.
Both 'should' be working, but don't have everything needed to test (cpu and hsf).