His test is described at http://communities.intel.com/community/openportit/server/blog/2009/09/26/the-one-million-iops-game
There's a YouTube video too. Sorry if I have the wrong group - bandwidth is a complex issue including many factors. Please advise if I should direct the question elsewhere.
Apologies for late reply, I don't frequent these forums very often and didn't see your post.
My solution was driving 4Gigs/s worth of data using all 5 PCIe x8 slots, its not a consumption of lot of BW by PCie standards, but yes theoretically you can drive 8GB/s (4GB/s one way) data on a x16 PCIe. I could possibly test this with larger chunk size read/writes and see maximum amount of data transfer i can achieve within SAS/SATA limits (3Gb/s per port). A modern graphics card might be a good candidate to test potential of a PCIe bus.