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Old 04-18-11, 10:05 PM   #5
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Join Date: Apr 2011
Posts: 12
Default Re: GTX590 riches only 553 MHZ with 270.40 and 270.41 drivers

Hi danix,
Thank you very much for your answer!

Originally Posted by danix View Post
Do you mean to say that each card works fine in isolation, but when two cards are installed, they both fail to clock up to the highest level?
Yes, exactly.

Originally Posted by danix View Post
Actually, now that I think about it, 1200W does seem a bit on the low side for two GTX 590s under load. The GPUs are probably staying clocked down because there's insufficient power. Not sure why this would work for you on Windows - do you still see the higher clocks even when under a heavy GPU load?
Yes, potentially the PSU could be one of the reasons and it sounds logical. The PSU was initially supposed to be the problem by Nvidia Linux team too.. However, I donít thinks that this is PSU problem because:

1) As you can see from the picture below, yes, under Windows there are no problems. I ran Heaven2.1 benchmark and simultaneously CUDA calculations on 4 GPUs and the clocks are fine. Our Cuda applications scale no so good as Heaven bench and SLI, thus about the GPUs load there is no logic (or I am missing something?) to be worse under Linux..

2) The cards work well in QUAD-SLI under Windows and there were numerous of the reviews and customers withhold any problems with +1100W PSUís and even less. So, why the problem is only under Linux?

3) Recently it was reported that the power consumption of GTX590 for a typical CUDA application is about only 260W.

4) I use certificated by Nvidia Quad-SLI PSU- Corsair AX1200.

Is it possible to be some driver limitation due to some power protection? Moreover, the cards not reach level 3 even without any load!? Or just bug in current Linux drivers?
I donít know, but really need of help and will be very thankful if you and someone other can help/fix this issue!! I am sure that this will be important for many others who plan to use these cards for CUDA.

I also kindly ask someone who has 2 GTX590 cards (or can obtain information from somewhere), just to see and report here if they both work at reference speed under Linux (with PSU 1200W or below)? Maybe Nvidia could perform such simple experiment just to be clear?

In the above example, the program Hex never scale more than 30-40% on 4 GPUs, i.e. this is normal.
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