The fastest Cel you can use is a 533, not the newer 533A. Your board is set up for 2.0 volts, I doubt there is an updated BIOS for it. The performance difference between a 366 and a 533 is not worth the price. Powerleap may make a processor/adapter but that is really expensive. Get a new case, MB and processor--use the other old parts for now. Don't waste $$ on the old machine, it has old memory type, slow hard drive (ATA33), the AGP bus will not take any newer cards, etc. Build a new computer. R