1. The P4GB has 5 PCI slots(just like the P4G8X and 8INXP), onboard Gigabit ethernet(like the P4G8X and 8INXP), onboard Firewire(like the P4GBX) and onboard audio(like the P4G8X and 8INXP). What it doesn't have that the other two boards have is Serial ATA support, RAID, AGP/PCI lock, memory...