There are a some motherboards out now that can more than 2 full PCI-e slots. The ASUS P6T6 WS Revolution motherboard, for example, can run 3 boards in full x16 speed. Many will run 3 or more boards, but few will have them all at full x16. This board, and I believe there are a few others out there by other companies, could run 3 GTX295's at once at full speed, though I don't have the money to buy 3 of those right now.

16 or 8x PCIe 2.0 is uncritical for now. It's a bit critical though to run 6 GPUs (3 cards) in one box.. concerning PSU, cooling and noise.

MrS

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Scanning for our furry friends since Jan 2002

pharrg wrote:

There are a some motherboards out now that can more than 2 full PCI-e slots. The ASUS P6T6 WS Revolution motherboard, for example, can run 3 boards in full x16 speed. Many will run 3 or more boards, but few will have them all at full x16. This board, and I believe there are a few others out there by other companies, could run 3 GTX295's at once at full speed, though I don't have the money to buy 3 of those right now.

Right at the moment I'm running 3 GTX295 combined with an ASUS Rampage II Extreme, 3 9800GX2 are used together with an ASUS P6T6 WS...and I've got an ASRock X58 SuperComputer capable of running 4 cards waiting for being tested with GTXs. So there are some boards out there now for a while waiting to be used for what they were designed for: heavy crunching... ;)

MrS wrote:

16 or 8x PCIe 2.0 is uncritical for now. It's a bit critical though to run 6 GPUs (3 cards) in one box.. concerning PSU, cooling and noise.

Both rigs are using 850W PSUs from Antec to feed the GPUs and i7-CPUs, both oc'ed...without any probs...and I got an 1250W Enermax PSU to be used if the four card configuration should work. All rigs are air-cooled...and about the noise: well, that's something one has to accept if he wants to run such highly performant rigs... ;)

I was pleased to see that you are running 3 295's on a Rampage II Extreme, as I just ordered a new system yesterday with that same card and 2 295's but didn't know if it had room for a third one, my wallet on the other hand is not so pleased to learn this. I thought I was going to be able to put off an upgrade for quite a while but now instead I find myself already trying to figure out how toafford a third one Crunching is proving to be an expensive habit but I think I am hooked at this point. If CPU's were Coke, GPU's are most certainly Crack.

You would need a case with 8 expansion slots to use three GTX295 together with an R II Ex, e.g. Lian Li V2010, Lian Li PC-P80 or an Lian Li V1000 Plus II (only 7 slots, but it will work)...

I was sorry to hear about needing 8 slots to install triple 295's, but you do mention a 7 slot case which can manage it, so I still have some hope, as my case is going to be a CoolMaster HAF 932 which has 7 slots. If not I save a few bucks.
If I am not using my system for gaming and won't ever need SLI functionality can I install a non 295 card in the extra slot, like a 280 or 285, or even my current 260.

Sorry, but I think it won't work in your case: the Lian Li I've mentioned has the mobo installed upside down, so there's some space between the end of the mobo and the top of the case, enough for the part of the GTX that's overlapping...
The combo of 2 GTX295 + another single slot card should work...