I use dual GTX 580s to test the performance difference caused by reducing the PCIe bandwidth. In the next little while I guess I’ll do another round of testing with a high end dual GPU card such as a GTX 590 or HD 6990 and test 4x/8x/16x to see how much difference there is.
SLI Using Dual PCIe 16x vs 8x – How Much Bandwidth is Needed? Linus Tech Tips
