Westmere internal PCIe link vs HT 3.0 NB one

I want to test latency with a K10 AM3 HT 3.0 NorthBridge PCIe x2.0 x16 link, and the one on an i5 which has it internal along with DDR controller over internal QPI. Is there a tool for testing PCIe bus latency?

I can't seem to find data on this. I do have two ITX boards(zotac H55 and ASUS M4A88T-I) I could test on though if there is a tool that can test PCIe link bandwidth. Too many other factors are included by just doing FPS test with similar CPUs and the same GPU I find.

I have one 8800 GT and a x4 615e and i5-650 for those boards, both with the same kingston CAS5 DDR3 1333 at 4GB. Search engines yield no data on this.

Thanks in advance.