HP Xw9400 HP xw9400 Workstation - Service and Technical Reference Guide - Page 91

PCI Express PCI Express is a point-to-point architecture and uses a serial data transmission protocol. A single PCI Express lane consists of four wires and can transmit 250 MB/s in a single direction or 500 MB/s in both directions simultaneously. This bandwidth is not affected by what is happening on other PCI Express buses or legacy PCI/PCI-X buses (provided that total bandwidth can be handled by the CPU and the memory subsystem.) The transmission protocol is somewhat similar to that used for a LAN connection and contains error correction and detection, packet addressing, and other network features. PCI Express improves system attributes. PCI Express enables a low-power, scalable, high-bandwidth communication path with a small number of connections (wires) compared to traditional parallel interfaces (for example, PCI). The PCI Express I/O slots can support other PCI Express cards with lesser bus bandwidth than what is physically defined for the slot. Use the following table to determine compatibility. For example, a PCI Express x8 card does not work in a PCI Express x1 slot, but a PCI Express x1 card works in a PCI Express x8 slot. Table 5-5 PCI Express compatibility matrix for xw9400 Slot 1* x16 mechanical x8 electrical Slot 2 x16 mechanical x16 electrical Slot 4 x16 mechanical x8 electrical Slot 5 x16 mechanical x16 electrical PCI Express Yes Yes Yes Yes x1 Card PCI Express Yes Yes Yes Yes x4 Card PCI Express Yes Yes Yes Yes x8 Card PCI Express Yes Yes Yes Yes x16 Card * Slot 1 is for short cards only. ENWW Removing and replacing components 81