Ironguts
I might be clutching at straws here, but the page of Asus motherboard info that you found has a copyright dated 1996, which was when the board was first manufactured.
The report gives the fastest processor speed at 266Mhz, but that would have been the fastest at the time of publication.
I am still wondering if I could bung a 350 or 400Mhz processor on the board.
Cheers SS