Both nice motherboards. It's mainly a 100MHz/1024KB vs 133 MHz/512KB cache difference. Don't know how much memory you want to put in it but if you want to deck it out I would go for the GA-486AM. Else for the GA-5486AL.

The AM model with the umc chipset has nicer “vibes”

With 1M L2 you can cache maximum RAM.

Although, for arcade games you probably need no more than 16-32MB.

The 5486AL looks cramped, but you don't have to replace or modify any Dallas/Benchmarq RTC module if empty. Hopefully it doesn't have battery damage.

I would also choose the GA-486AM, the IDE connectors at the bottom-right look clean.

But the best mainboard in terms of performance, I don't know. Maybe you can conduct some benchmarking. 😀

st31276a wrote on 2025-03-07, 07:10:

The AM model with the umc chipset has nicer “vibes”

With 1M L2 you can cache maximum RAM.

Although, for arcade games you probably need no more than 16-32MB.

Cache size isn't just for maximizing RAM size. Larger cache size usually also increases performance.

Yes that too 😀

Although, the effect typically declines as cache size is increased, especially for typical 486 applications.

There is some battery damage on the 5486AL but it’s only surface damage and hasn’t broken any tracks as far as I can tell.
The board posts and the keyboard works in the BIOS.
I haven’t tested any further yet.

I’ve ordered a new Dallas module for the AM board.

Yes, I’ll try to do some benchmark comparisons.
Which apps are recommended for those benchmarks?

I’m leaning towards the 5486AL.

Phil's Dosbench is a good start I think, it has all sorts of benchmarking tools. Maybe you can post some results here, I'm curious.