Hey those old 333 celerons can be over clocked to run @ 100 mhz
IE 500MHZ and yes dual mobo's mean dual cpu's. You could only do it with specially modified celerons or regular cpu's. It used to you used these special slot1 cards which took the cpu's and hooked up 2 of em. I used to have a dual pentium pro
150 mhz that could over clock to 200. Running those 3 gig dirves in raid 0/1 for better performance since NT had just come out with built in support for it.
Think they stopped making 440 stuff in 99-00 at least. Bu tjust adding 100MHZ ram and changing the jumper from 66MHZ to 100MHZ you have a 33% faster system. I had one for a few years and it was reliable. Mostly