P4IBAS2 v1.0A ,maximum CPU and HDD supported information as below, HDD:250G Socket 423 CPU , Pentium 4 400Mhz FSB OLGA CPU : 2.0G Socket 478 CPU , Pentium 4 400Mhz FSB (256K/512K L2 cache) CPU – 2.4G. Pentium 4 533Mhz FSB (512K L2 cache) CPU –No support Pentium 4 800Mhz FSB (512K L2 cache) CPU –No support Celeron 400Mhz FSB (128K L2 cache) CPU – 1.8G Mhz Pentium 4 533/800Mhz FSB (1M L2 cache) CPU – No support Celeron D 400Mhz FSB (256K L2 cache) CPU – No support PS: CPU daughter board is needed for 478 socket CPU