Does Pci express lane width matter?

So, lets say i have a motherboard that has x16,x8,x4 pci express slots. I plug in three opencl capable cards in there. Does the lane width affect opencl performance?

Essentially, am i better off getting three motherboards and doing one card each or can i do one motherboard with three slots as above?

Does the lane width affect opencl performance?

Yes, a lot. I would not install a card on a x4 slot.

Essentially, am i better off getting three motherboards and doing one card each or can i do one motherboard with three slots as above?

The problem you would have them is now to distribute the work across different systems. You can use MPI or similar to do that, but it’s going to be quite a bit more work than working on a single system.

As David says, you’d be dealing with a different sort of problem once you get out to multiple systems with one card on each. It’s not impossible to handle (Thibault 2009) does it with CUDA and POSIX, but you’ve got some extra problems to handle.

The easiest solution here is just get a different motherboard that supports 3 x16 slots. I can think of several in the $200 price point. It’d be easier (and cheaper) than buying three separate boxes, all the networking equipment, etc.