PCI Express Platform
PCI Express is the standard platform for all current PC based systems and also for the future. Today?s State-of-the-art motherboards normally have a couple of PCI Express slots but only one or two PCI/PCI-X slots. The PCI Express bus is a point to point connection allowing full speed for every single slot. The Express bus is freely scaling and is available with 1 lane (x1), 4 lanes (x4), 8 lanes (x8) and 16 lanes (x16). For mechanical compatibility connectors may have more lanes than are connected to the motherboard.
PCI Express Lanes
PCI Express Generations
The first PCI Express generation was introduced in 2005 and is working with 2.5 GHz clock generating a raw data rate of 250 MB/s (including 20% protocol overhead). In 2007 the second generation (Gen 2) was introduced doubling the clock rate to 5 GHz and being backward compatible to PCI Express generation 1. In 2010 the specification of PCI Express generation 3 was released, again being backward compatible to Generation 1 and 2 and again by doubling the transfer rate compared to Gen 2.