Poor performance with two GTX 480's SLI

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csflame4

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I noticed yesterday when I ran 3D Mark Vantage that the Graphics score is much lower than it should be at with these cards. Ive already ran 3D mark vantage multiple times before and got a correct score. My normal score is about 40k in vantage, yesterday it was only hitting 32k and the GPU score was 27k, usually that is around 35k

Here is my best vantage score, remember that now my cards can only hit 27k, and this just happened out of nowhere, I havnt made any changes to my comp.

http://service.futuremark.com/compare?3dmv=2267051

I also noticed odd behavior with the cards, at some points in the graphics test the FPS will be where it should be, at other points it is much lower than it should be, the fps range is about 25 to 150 in the Jane Nash test. I have already reinstalled the drivers. Also the GPU usage is going all over the place, from 45% up to about 95%.

I tested each card by themselves and they both run fine, they get around 19k each on vantage. The GPU usage also stays at about 99% during the whole test, it doesnt fluctuate as much as it does in SLI. I have messed with the AFR settings in the Nvidia control panel and the multi display mode and neither of them makes a difference.

I have reflashed the BIOS and left everything at default and then I got a 22k GPU score. I then overclocked my system to my normal settings and it got a 27k score again. When the single card is running it seems to run smoother and the FPS range doesnt change so much.

Both cards are running because even a 27k GPU score is to high for a single 480. SLI is enabled in nvidia control panel also. The temps for both cards are also fine, they are actually lower than what they normally get in vantage

I have gone from the newest 257.21 drivers, the 257.15 beta drivers and the 197.41 drivers and they all have very poor performance when running SLI. I also have a back up windows 7 partition and I ran Vantage on that and it still got the low Vantage score, so it cant be some setting in windows when they both get the same score. The windows 7 rating score actually got a 7.8 for the graphics card on default settings, two GTX 480's SLI only getting a 7.8?

http://service.futuremark.com/compare?3dmv=2267051

Any ideas what is wrong here? I have pretty much come to the conclusion that there is something wrong with the motherboard.

i7 950 @ 4.13
12Gigs of DDR3 1600Mhz @ 1803Mhz
EVGA SLI classified E760


 
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AMW1011

AMW1011

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Forget Vantage, test some games. You can never be sure what is happening with synthetics. This does sound odd, but I wouldn't worry unless there are problems in games as well.

Oh and HOLY SHlT, 35K IS MASSIVE. My dual 8800 GTS 512mbs top out at 11.5k stock and 13k overclocked... :( Still not upgrading this round though, but it is SO TEMPTING. Anyway, nice cards, hopefully we can get them straightened out.
 
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csflame4

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Yea that makes sense, but its just frustrating because their not scoring were they used to in vantage. I guess I have OCD with this kind of stuff, if something isnt running right in my computer I have to fix it, even if its still getting a 27k GPU score, yea thats still high but not were it should be, haha

I will play some battlefield bad company 2 tonight and see if it plays the same. Now that I think about it the cards have the same behavior in that game as they do in vantage. Like I mentioned before the FPS will be really high, and then get really low, like to low for these cards. When I tested the cards by themselves they each were getting higher fps than the lowest fps they were getting in SLI... if that makes any sense at all, I didnt explain that very well, lol

In bad company 2 i get slight visual lag sometimes with these cards, the fps goes as high as 140 and as low as 30 with max settings @ 1900x1200 res. Doesnt that seem to low for these?
 
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AMW1011

AMW1011

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Hmm my first thought would have been RAM, but since they are fine in a single config. I'm not sure. I'm afraid it sounds like your PSU, perhaps it is having problems powering your setup. The PSU might have degraded suddenly or has been damaged, it happens, and these cards pull some serious juice. What PSU do you have? Do you have a friend with a 1KW PSU that you could borrow?
 
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csflame4

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I have a 1200W thermaltake PSU, is it possible that my PSU can just loose performance like that but still "work"?

I was thinking the same thing about my PSU, but i threw that idea away because I didnt think they could just loose performance like that.

In SLI the cards still hit really high FPS at some points, around the same FPS it hit before, could that still mean the PSU just cant hold the wattage thats needed? it can only hold it sometimes?

I have a friend with a 1000W Corsair PSU
 
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AMW1011

AMW1011

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Yes a damaged PSU can act like that, though it is somewhat rare. Call up that friend and see if you can borrow it for a test run, make sure to check all connections before you do the switch in case it is a bad connection. Also did you try taking out the cards and putting each in separately and checking them or did you just disable SLI in nVidia control panel? The slave card may be damaged which could account for your problems.
 
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AMW1011

AMW1011

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That should do it, but I would recommend taking them both out and re-seating them. You could also try putting only one in at a time in the same slot. This is a longshot, but its relatively easy and it will eliminate some variables. I wouldn't call these steps necessary by any means, but its worth a try if you have spare time. Then again I tend to be a bit OCD about problems.
 
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csflame4

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Just thought I would post an update, I am still having the problem but i am almost certain now that it is the PSU. I just ran Vantage four times, three times at no OC, one time at full OC. All three times with the CPU not OC'ed I got a normal score 36383 P score with a 32442 GPU score. The one time I ran at full OC I got a 27k GPU score.

So it seems my PSU cannot power two 480's and a high OC'ed cpu

EDIT:

Well the problem isnt the PSU, the problem was that I had the CxE function enabled on the bios, I turned it off and now everything is performing corectly, just got a 40.6k vantage score.

Is there a setting I can set the CxE function to so that it doesnt do this? i like when that is enabled because it reduces my idle temps by 8 to 10 degrees C
 
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