PCI-X and PCI Express

[NeedHelp]

PCI-X and PCI Express - Are these one and the same?

[kromagnon]

nope, different.

[xXHalfSliceXx]

Peripheral Component Interconnect - Wikipedia, the free encyclopedia

PCI-X - Wikipedia, the free encyclopedia

[Jordan]

PCI-Express, on the other hand, uses a serial interconnect along a switched bus dedicated exclusively to that slot. In this respect, and most others, it uses radically new architecture, having little to do with old PCI. Furthermore, PCI-Express has the unique capability of multiplying up individual data "lanes", to produce aggregate interconnects that can deliver up to 16 times the bandwidth of a single lane. This is why you will always see PCI-Express slots referred to as "PCI-Express*4" or "PCI-Express*16" etc.

PCI-X uses a parallel interconnect along a bus that is shared with other PCI-X devices, just like PCI. In fact, PCI-X is best thought of as "PCI-eX tended", as it is simply an extension of the legacy PCI 32-bit format, with which it is backward-compatible. It differs mainly in the fact that the bus is now 64-bits wide, and runs at higher frequencies (now up to 533MHz, compared to 66MHz - the fastest PCI frequency).

Check The Difference Between PCI-X and PCI-Express - Electronics Nexus for more and for the source of the quote.