Is it possible to use four GTX 690 cards in one computer (on a motherboard with four PCI express slots) for CUDA ?
Yes it is! And it is awesome :)
Nice, what kind of power supply do you use?
Don’t know the brand. Just find something with enough wattage.
Yes, but what is the required wattage? 1500 W?
A GTX690 has a “Maximum Graphics Card Power” (TDP) of 300W. Normally GPUs use less power when doing compute than in gaming, but I usually go for the worst case scenario when selecting a power supply. 300W times 4, plus 100W for a CPU, and some more for peripherals (mother board, RAM, harddrive, etc), and 1500W should be fine.
Keep in mind that when you put 1500W of power into your computer, it will (all) exit as heat. 1500W is a lot of heat to deal with, similar to a water heater (to make tea) or a 2 horse power engine which can power a boat. So you better have a plan on how to get all that heat out of your computer, or it will shutdown in no time due to overheating.
Yes my previous computer had 3 x Nvidia GTX 480 and used about 950 W with CUDA. The computer room was clearly warmer than the other rooms…
Take care as well to check that your power supply comes with enough cabling for plugging in all the cards. GTX 690 require 2 8-pin power connectors each, which is not so commonly available I guess, even for a beefy PDU.
Which single CPU motherboard can take four 690s?
The good old Asus P6T7 WS SuperComputer takes for four double height graphic cards, all can be connected to a true PCIe 2.0 x16 slot. I use this one with four GTX570’s using Linux, I haven’t tested four dual-GPU cards in one machine, there might be driver issues with 8 GPUs in one computer. (Maybe someone from Nvidia can comment on that?)
And there is the new Asus P8Z77 WS which will take four double height graphic cards with PCIe 3.0, but only at x8 speed. An Ivy bridge Intel CPU is required to get PCIe 3.0 speeds, otherwise you only get PCI 2.0. But in theory a 8x PCIe 3.0 connection should give a higher bandwidth than a 16x PCIe 2.0, due to the new 128b/130b encoding scheme.
Other motherboards which can take four cards are out there, but it is hard to find one on which you can connect four dual-height cards at full PCIe speed.
Another board that’s coming (maybe) is the ASRock Extreme 11. It has 4 PCIe 3.0 slots at x16 speed because it has dual PLX PCIe 3.0 PEX8747 switches onboard. Hopefully they ship it.