question for the GPU gurus: how important is having x16 lanes for GPU crunching?
looking to buy another pc, dedicated cruncher, so multiple gpu's
looking at motherboards, getting 3 or 4 gen2x16 slots that will all run at x16 means a very expensive mb
however, if x8 or x4 is not a bottleneck for crunching, then i can spend less on the mb and more on the GPUs!
thanks
Depends on how big the cards you are planning to buy are. In my rig, an x8 slot seems to be insufficient to display wallpaper and crunch with a 5970.
What flavor of cards are you leaning towards?
EDIT: I should say this is in my experience, relating to my own rigs or anything I can read on the 'net about this topic:
With all due respect, I'm not sure exactly what the post above mine is referring to. You would be hard pressed to saturate even a 4x PCI-e lane slot when crunching with current GPUs. Let alone an 8x or 16x lane slot! Maybe in the distant future the GPUs will get so powerful that they will need a faster data pipe for data I/O when crunching, but currently, the time spent in data transfer is actually a very little part of the equation. Most of the time, the GPU is crunching the data it was given.
Realize, this "crunching" we do is a very different scenario for the mobo/GPU I/O path than say, playing a high end graphics game like Crysis at 60FPS, where the GPU "needs" 16x speed to transfer data in real time.
Last edited by DrPop; 01-31-11 at 06:41 PM.
My 2x5970 rig has an x8 and an x16 slot. Cards will not work, except in crossfire. My only point is that if this is going to be super-duper top of the line cards, there may be issues...Originally Posted by DrPop
Ah, OK, I see what you're getting at, then. I guess the answer is, "it depends on the exact cards in the setup."
So...I think we can safely say that for normal use GPUs (the 5970 is a special scenario, because there are 2 GPUs on the card, so Maxwell is running 4GPUs in his rig out of 2 PCI-e slots!)...I don't think you'll have much problem with a more usual setup.
But, he is correct - please let us know the model(s) of motherboards and GPUs you're looking at and we can give a much better and more accurate answer.
Last edited by DrPop; 01-31-11 at 06:52 PM.
Let me hijack this thread temporarily. I seem to remember there being a hack where you could modify a PCI-e card to fit into a 1xPCIe slot. Or was that a different speed slot? The reason I ask is that this Dell does have one 1xPCIe slot and I have an nvidia card that will just barely crunch, that I could put to work possibly. Also, my mom just gave me a dremel tool.
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