Quote (HyphyIll @ May 14 2015 08:23pm)
The 8350, for example, has 16 PCI lanes. So if you run one card in a slot that is 16x it will run at 16x.
When you use 2 GPU's it reduces the amount of lanes per GPU depending on your chip. In this case, 8 each GPU, regardless if its in a 16x slot or not.
If you had a 5xxx series for example, those chips allocate 40 lanes so you could run 16x 16x no prob.
The difference between 16x and 8x isn't even noticeable so 8x 8x is okay but bottlenecking does begin at 4x.
So if you run tri fire (or SLI) on a chip that only has 16 lanes it will be 4x 4x 8x, which isn't ideal.
Yep.
Except SLI just stops working due to drivers or other NVidia shenanigans when below 8x. (link in my earlier post, also one Linus' video shows that quite well, he tests 4-way SLI with 2 different x99 i7's with different lane counts, GPU's were 980 iirc)