GPU rendering performance and PCI Express bus speed

Hi there,

I’m trying to price out an inexpensive 4-gpu cycles rig, I have 2 750ti’s right now, want to get a motherboard with 4 PCI-x slots and add two additional cards for a quick speedup. There are a number of well-reviewed motherboards on the market that don’t have 4x PCI 16x, but rather 2 16x and 2 4x, or some combination there-of. My question is, does that speed impact rendering performance significantly? Seems to me that there isn’t necessarily a great deal of I/O happening compared to the processing that occurs on the cards themselves so perhaps that wouldn’t cause a bottleneck?

Thanks for the support all, can’t imagine where I’d be without these forums.

-Charlie

My question is, does that speed impact rendering performance significantly?

No, you loose a few miliseconds during uploading the scene to the GPU but render performance is the same.

Cheers, mib