mt777 wrote on 2020-06-09, 21:29:

I have a few questions which couldn't find clear infos.
1) P90 runs with FSB 42MHz. Is possible to run stable with higher cpus (for example with P100?) Which VLB cards can handle ~50MHz ?

Yes. The Nx586 P100 runs at 93 MHz and the board does support it.

That produces VL-Bus at 46.5 MHz which is passable, but many VGA cards will need to add a waitstate reducing performance somewhat.

However, it is less problematic than VL-Bus on 486 DX-50 for example. This is because NexGen VL-Bus cards are not directly connected to CPU local bus, like on 486, but the signalling on VESA slots is facilitated by the chipset.

mt777 wrote on 2020-06-09, 21:29:

2) PF100 - I read that PCI version supports PF cpus. Maybe does exist some kind of hack to run with on VL version too?

I don't know about any such hack.

so only possible upgrades (from P90) are finding P100 and cache to 1MB?

Not sure if you can upgrade the cache. It is soldered on the mb and there are solder pads for bigger chips so in theory, yes, but I thought the L2 cache on NexGen is 4-way associative rather than direct-mapped so upgrade past 256kB shouldn't be necessary...