It should be related to SANDRA 2001 utility only support for FAT32 formatted , if HDD formatted as FAT32 that got same transfer rate .

Intel 845 chipset cannot support registered SDRAM, but ECC SDRAM.

No, the P4IBAD V1.1 comes with Intel ICH2 chip which supports USB 1.1 only.

Yes, the P4IBAD V1.1 supports hard drive capacity up to 160GB.

No, the P4IBAD V1.1 supports AGP mode up to 4X (1.5V only). You can install an AGP 8X card on this MB but the card will run with AGP 4X mode.

No, the P4IBAD V1.1 supports DDR RAM up to 266MHz.

P4IBAD v1.1 MB ,maximum CPU and HDD supported information as below, HDD:250G 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