P4VXAD v1.0 maximum CPU and HDD supported information as below,
CPU: Pentium 4 400Mhz FSB (256K/512K L2 cache) CPU – 2.4G.
Celeron 400Mhz FSB (128K L2 cache) CPU – 1.8G
BIOS newest revision will solve this issue.
No, the P4VXAD v1.0 only supports to DDR266 maximum.