Are PCI-X and PCI express the same thing?

[wenty]

Hi Folks,
I know something about PCI,but I do not know a single thing about PCI-X and PCI express. For the last two, are they the same? Anyone can recommend some simple description about them? Thanks in advance.

--wenty

 

[Pinczakko]

PCI-X and PCI Express is a two different thing. PCI-X is actually a bus protocol that is an "extension" to PCI, PCI-X is not a point-to-point bus protocol as in PCI express, but in the PCI-X 2.0 I think PCI-X is much like a point-to-point bus protocol implementation, due to loading issue in the highest bus clock supported by the protocol. Both PCI-X and PCI Express is backward compatible with PCI protocol in terms of software implementation, but it's a different thing in hardware though, PCI-X slots is pin and electrically compatible with PCI, on the other hand PCI-Express is NOT pin compatible nor electically compatible with PCI.