Thanks a lot Malik. I'm really pleased that I've been able to get some good performances out of this old M919 board. There's no doubt it can do 160 MHz, and it is still solid in DOS @ 180 MHz, and only requires the BIOS cache timings to be loosened up a bit for solid Win98 use @ 180 MHz.

Hmmm an M919 with real cache? How odd, a rarity indeed 😀

Regarding the 4V / 5V volts issue. I think I have worked out what the jumper specifications mean. If you want 4V, you adjust jumper JP23. However, if you want 5V, you leave JP23 alone, and simply alter the "3.3V or 5V" set of jumpers elsewhere on the board.

I'm a bit late to the party on this but yes, this was my experience too.