Multi-GPU crunching

[VirtualLarry]

As mentioned here http://forums.anandtech.com/showpost.php?p=30771063&postcount=33 , it seems that doing multi-GPU crunching under Windows 7 with NV drivers no longer requires a dummy plug in each GPU?

Can someone else confirm this? Anyone else running multi-GPU crunching under Windows 7 with Nvidia cards?


Secondly, Newegg currently has some nice items on sale that would be of interest to multi-GPU crunchers.

Lian-Li mid-tower Aluminum case with window, has EIGHT expansion slots, good for those quad-PCI-E slot motherboards that are alternatively spaced, so that you can use FOUR double-width graphics cards.
http://forums.anandtech.com/showthread.php?t=2120990

ABS 1050W continuous modular PSU, seems to be a variant of the Enermax 85+ 1050W PSU, which retails for $270. Newegg has it for $135 now.
http://forums.anandtech.com/showthread.php?t=2121074

 

[brownstone]

I'm folding (or was) on 2 gtx 460's with no dummy plug. I'll see if I can find a link to show you how.

 

[Peter Trend]

I posted in the other thread, just repeating that I'm running three 8800GTs in Windows 7 Premium x86 with no issues whatsoever. Desktop was automatically extended by Windows without using a dummy plug. You don't even need a monitor plugged in to the first card if you use a remote desktop program.

Could anyone recommend a good motherboard for four GTX460s? CPU not important.

Thanks for the heads-up on those PSUs VirtualLarry!

 

[VirtualLarry]

"v258.xx drivers seem to resolve the dummy plug issue for all OSes, as reported on the folding forum by Leonardo."
I found that mentioned in a couple of forums. I'll have to try that.

 

[brownstone]

Could anyone recommend a good motherboard for four GTX460s? CPU not important.

http://www.newegg.com/Product/Produc...82E16813130274

This one is what I've got, but if you can find the last generation one (MSI 790FX I think) you can probably save some dinero.

 

[Peter Trend]

Thanks. Can't afford either, yet! LOL...

 

[Markfw]

http://www.newegg.com/Product/Produc...82E16813130274

This one is what I've got, but if you can find the last generation one (MSI 790FX I think) you can probably save some dinero.

You can use 3 double or 4 single cards in that, not 4 double.

 

[Peter Trend]

You can use 3 double or 4 single cards in that, not 4 double.

Which one? Looks like they would both fit four double-width cards to me, but not inside a case, bottom card would need space to overhang. It would have to be PCI-e 2.0 x8 x8 x8 x8 though.

 

[ZipSpeed]

Certain cases should be able to fit 4 doubles if designed for it. Anandtech just reviewed the Corsair 600T on the front page and I think I remember it mentioning an 8th slot for use with double-slot video cards or accessory (such as a USB bracket).

 

[brownstone]

You can use 3 double or 4 single cards in that, not 4 double.

4 doubles will work, if you can figure out the cooling part of the equation.

 

[Peter Trend]

Thanks, I thought so. Case would be the one I built for my folding farm, it has space for three motherboards full of GPUs and three PSUs, and about 3-4 120mm fans per motherboard. Will have to bore a hole in the side to let air get the the bottom card, but it's 2mm steel, not too difficult...not as difficult as affording the hardware in the first place, anyway!

 

[petrusbroder]

For a folding farm of such magnitude, why not water cooling. Why not use a larger radiator (e.g. from a small car), a large enough pump and a large enough coolant volume and you need no heating in the house/appartment?
I am seriously considering a similar setup for my computing farm - but in separate cases: all computers coupled to a heat exchanger which I already have. Only the pipes have to be run and - of course the stuff needed for the CPUs and GPUs.

 

[brownstone]

For a folding farm of such magnitude, why not water cooling. Why not use a larger radiator (e.g. from a small car), a large enough pump and a large enough coolant volume and you need no heating in the house/appartment?
I am seriously considering a similar setup for my computing farm - but in separate cases: all computers coupled to a heat exchanger which I already have. Only the pipes have to be run and - of course the stuff needed for the CPUs and GPUs.

Every time I hear of this it fascinates me, but I have so many questions. How does one hook their computer to a heat exchanger? I understand the concept of the heat exchanger, but what exactly are you using? So many questions...any pictures or blueprints...or both?

 

[Peter Trend]

For a folding farm of such magnitude, why not water cooling. Why not use a larger radiator (e.g. from a small car), a large enough pump and a large enough coolant volume and you need no heating in the house/appartment?
I am seriously considering a similar setup for my computing farm - but in separate cases: all computers coupled to a heat exchanger which I already have. Only the pipes have to be run and - of course the stuff needed for the CPUs and GPUs.

I'd love to say "no reason" but for me it has to be the high cost of all the water blocks. However one could then use single-slot server boards e.g. a dual-Xeon Tyan with 7 PCI-e slots. I like that idea. I'm definitely planning to heat my house with waste PC heat in any case.

FWIW I'm sharing with 7 other people at the moment so can't just shut the heating off for the whole house. However, I have had my radiator turned off for the last month, and my bedroom still gets warm enough to justify leaving windows open slightly, even though it's -3C outside now! Drawing ~750W at the moment.

Please build it Peter!

Was thinking you could also have a water-divert valve to a second car radiator positioned either outside your house or inside a big tank of water (e.g. boiler feed tank) - for when the house is warm enough already, or for extra power-dissipation capacity, or just when you want to bring water temps down. Automate the valve with a thermostatic switch and you have added a safety feature!

 

[VirtualLarry]

The Lian-Li case that was recently in Hot Deals for $80, has 8 expansion slots. I picked it up specifically for a future cruncher build.

In other news, I couldn't wake my quad-GPU rig up today when I moved the mouse. It's a little disturbing. I was able to hit the RESET button, and it booted up again, and all four GPUs were present in the Display Advanced Properties page, so I didn't loose a GPU, although I wonder about the RAM. (Actually, I took the 2GB Gskill out of that rig, and put it into another rig with another 3x2GB Gskill, making 8GB, and all 8GB was detected by the BIOS, so I don't think that the RAM died. Wierd.) Last time my quad-GPU wouldn't wake up, I lost a GPU, and then some RAM.

 

[petrusbroder]

Every time I hear of this it fascinates me, but I have so many questions. How does one hook their computer to a heat exchanger? I understand the concept of the heat exchanger, but what exactly are you using? So many questions...any pictures or blueprints...or both?

I'll try to explain it. It is somewhat OT ...
In my attic the warm outgoing air from the house (especially from the computer room, bathrooms, kitchen) is forced through an air-to-air heat exchanger warming the cold incoming air.
The heat exchanger has an option to connect a water radiator which can heat the incoming cold air even more, especially when it is cold outside. Normally that radiator would be connected to a warm water source ...
I plan to connect the radiator in the attic to my computers through isolated pipes going to my computer room. In the computer room I would have 10 liter holding tank for the "cold" coolant. From the holding tank a bigger pipe would go to a pressure regulated pump; from the pump the tubing would go to the computers. From the computers all the tubing would be connected to a smaller tank (5 liters) which would be isolated, from that tank isolated pipes would go to the heat exchanger in the attic thus forming a closed system. I think I may need a pressure regulated pump at this part too, but I have not done that math yet.

Each computer would have a water block for the CPU and GPU(s). The tubing would be as short as possible to minimize friction.

In this way I would cool the CPUs and GPUs more efficiently and only the heat from the PSUs, and the other electronic components would be needed to be moved by air.

 

[Peter Trend]

This makes a lot more sense reading it the second time. I hope you go ahead with this soon and post the pictures here!