[angoragoats]

While you're technically correct, assuming you're using PCIe 4.0 or higher, the performance difference between x8 and x16 is practically zero.

[metadat]

Is this because the graphics cards are not using all available PCIe bandwidth? Or why?

[angoragoats]

Yes. In fact, even running a video card in a 4x slot (again, assuming PCIe 4.0) results in only a modest (5-20%, depending on what you’re doing) drop in speeds.

[Tepix]

Even for training?

[angoragoats]

I haven’t done a ton of training but everything I’ve heard and read indicates that PCIe 4.0 8x provides enough bandwidth for just about any application. You might see a negligible drop in performance, but no more than a few percent.