I think about to build a new PC.

Would be this combi possible: i7-4930K + 4x HD7990 (dual GPU card) ?

This would mean the 6 core- / 12 thread- CPU need to manage 24 SAHv7 or APv6 GPU WUs simultaneously.

This could work, or this would be too much for the whole system?

Thanks.

* Best regards! :-) * Philip J. Fry, team seti.international founder. * Optimize your PC for higher RAC. * SETI@home needs your help. *

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Buy a mobo with 4 pci-e slots, buy big a$$ power supply and go for it.
Seems simple enough.

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Buy a mobo with 4 pci-e slots, buy big a$$ power supply and go for it.
Seems simple enough.

One power supply is not enough for 4x HD7990 + the system.

He will need 2 or more.

I use 3 for my top rig.


Tim

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Depends on how much CPU the ATI apps require for support on GPUs. For example, I know the NVIDIA AP GPU app requires a full CPU core for support, so (if ATI is similar) you would need 24 cores to support your max theoretical 24 APs at once.

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Buy a mobo with 4 pci-e slots, buy big a$$ power supply and go for it.
Seems simple enough.

One power supply is not enough for 4x HD7990 + the system.

He will need 2 or more.

I use 3 for my top rig.


Tim

Tim. The additional power supplies, are you using paperclip trick?

Also. To the OP. I was looking at some HD7990 and it looks like some of them take 2 slots, some take 3 slots. If you get cards that take 3 slots, you will not fit 4 cards on one mobo.

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Buy a mobo with 4 pci-e slots, buy big a$$ power supply and go for it.
Seems simple enough.

One power supply is not enough for 4x HD7990 + the system.

He will need 2 or more.

I use 3 for my top rig.


Tim

Tim. The additional power supplies, are you using paperclip trick?

No, I am using this one.

http://www.frozencpu.com/products/image/5637/cpa-167.jpg/cpa-167/Lian_Li_Dual_Power_Supply_Adapter_Cable.html

Tim

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I have a 1250 W Enermax PSU (which feeded the 4x GTX260 PC).
Maybe for the CPU/mobo & additional stuff (HDD, fans, and so on ..) and 2x HD7990.
I calculate with 200 + 300 + 300 W.

I have a new 950 W Corsair PSU here. Maybe for 2x HD7990. I calculate with 300 + 300 W.
This should work, I guess.

The HD7990 can OpenCL 1.2.
So the run time ≠ CPU time.
(postid=1417847)

Tim, which PSUs (manufacturer, wattage) you installed, how much they are loaded/used (wattage)?

Thanks.

* Best regards! :-) * Philip J. Fry, team seti.international founder. * Optimize your PC for higher RAC. * SETI@home needs your help. *

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Here is an old picture of the machine with 2 PSU. Later I add one more because GTX 590’s are VERY hungry.

http://s1343.photobucket.com/user/Timol1/media/DSC_1920.jpg.html?

I have one PSU for the system only, one PSU for the two 590’s, and one for the rest two 590’s.
As you can see from the list below GTX 590 need 46A and a 700W PSU minimum according to MSI. Corsair AX1200 give 100Amps on a single rail.

http://forum-en.msi.com/faq/article/power-requirements-for-graphics-cards

Tim

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I have a X-650W Seasonic running a 7990 XT2 + i5 3570T.
The GPU is undervolted to 1.02V resulting in a max power draw of 300W total system power.

Which means my PSU is only at around 50% usage. At 1.2V (standard voltage) the system uses around 450W.

For 2x 7990 I would get a 850W psu.