Bus specification designed to supersede PCI. PCI Express (PCIe) provides several improvements over its predecessor:

• It enables Quality of Service (QoS) which is a means to prioritise more time critical traffic (like an audio or video stream) to reduce break up.
• Supports multiple lanes that can be aggregated for a single link to provide increased bandwidth. (Each lane can transmit up to 2.5gb/sec, and the protocol supports up to 32x)
• Uses a point-to-point bus topology where a shared switch replaces the shared bus that PCI used.

NB: PCI-Express is sometimes referred to as 3rd generation I/O (3GIO)architecture.