A quick look at chipset PCI Express performance
 

In addition to support for Sandy Bridge CPUs, Intel's latest P67 Express core-logic chipset brings with it two major improvements over the old P55: a couple of 6Gbps Serial ATA ports and full-speed PCI Express 2.0 lanes throughout. Those features have been present in AMD chipsets since the SB850 south bridge debuted some ten months ago, making Intel more than a little late to the party. At least on the SATA front, the wait was worth it. While comparing four mid-range P67 boards, we discovered that Intel's 6Gbps Serial ATA ports are faster than AMD's.

So, what about the P67's PCI Express lanes? Those familiar with the P55 will remember that it, too, has PCIe lanes claiming second-generation status. But those lanes run at half speed and offer no more bandwidth than gen-one PCIe links. The P67's PCI Express 2.0 lanes are cranked up to the standard's full 5.0GT/s data rate, setting up a three-way comparison with the P55 and AMD's SB850.

http://techreport.com/articles.x/20241