Nisu samo grafičke kartice problem. Moderni SSD-i su na PCIE-u.
"Overall, the results of our testing is pretty mixed. With a single Titan X, we saw a wide range of results between using a PCI-E 3.0 slot at x8 and x16. Some applications (Unigine Heaven Pro and Octane Render) showed no difference, while others (Ashes of the Singularity, GRID Autosport, and Davinci Resolve) showed up to ~5% difference in performance.
At this point, we would say that if you are using a high end video card like the Titan X (Pascal) or possibly even a GTX 1080, it is probably a good idea to try to use a PCI-E 3.0 x16 slot - especially in multi GPU configurations. Depending on the applications you use it may not make much of a difference, but the fact that we saw a 10-30% drop in performance with x8/x8 compared to x16/x16 in a couple of our tests just goes to show how large of a difference it can make in certain situations."