I think i found the problem - bus speeds. The Celeron 600 uses a 66 Mhz FSB. My board is set to use a 100 Mhz bus. The P3/1 Ghz, on the other hand, uses a 133 Mhz FSB, which means that its out unless I overclock the board to 133 Mhz (and replace two of my PC100 DIMMs with PC133 modules), if i really want to do that...