ASUS P5E3 Deluxe/WiFi-AP @ Hardware Secrets
“Intel X38 is a high-end chipset featuring everything P35 (a mainstream chipset) has plus additional features. The main new feature of X38 compared to P35 is the support for the new PCI Express 2.0 bus, which doubles the maximum theoretical transfer rate of the add-on card you are using, if it is also PCI Express 2.0 (at this moment the only PCI Express 2.0 video card available is GeForce 8800 GT).”