Help with SLI - need expert help

[ossycowboy]

520 coz powerstream
fx 55
1 gb ocz 3700 platinum
2 x 74 raptors on raid 0
2 x xfx 6800gt


My system crashes everytime i play a game in SLI after about 30 seconds. I've tried bios update, switched cards around - eveything is fine apart from that. I have also plenty of fans in there. Has anyone else encountered this problem, molex is in ez plug too . Arghhhhhhhh

 

[GuitarDaddy]

Are you running stock settings?

You might try upping the RAM volts. This board sets default RAM volts at 2.6, but the spec for the OCZ calls for 2.75. I run my OCZ at 2.8 wether I'm overclocking or not.

Does the system run stable with 1 of the 6800gt's
I would try running with one VGA card, and run memtest, Prime95, 3dmark etc...
If everything checks out with 1 card, swap and run the same tests with the second card in single mode.
If everything checks out with both cards in single mode, that would eliminate the possibility of a bad VGA or a problem with CPU or RAM, and would point to the SLI function of the board.

If one card tests out, and the other doesn't, you may have 1 bad VGA card.

If you can't successfully run the tests with either card, you may have a problem with CPU or RAM or the motherboard. Then look to your individual tests for the answer. If both scenarios fail memtest, its most likely your ram. If memtest passes but Prime95 fails its most likely your CPU. If you get sporatic (non repeatable) results, its more likely the mobo.

Hope this helps. Good Luck!

 

[ossycowboy]

Thanks for your time, i'll try what you suggested

 

[ossycowboy]

Both cards are fine on their own. There should be enough power from the PSU 'cos i only have, 2 hard drives on raid 0 / ram /cpu / 2 cards / dvd rom drive /floppy /4 fans. It runs faultless and incredibly quick in sli mode but then shuts down after minute which is very annoying.
I've tried tinkering with the voltages but have had no luck

 

[bap4201]

what game r you trying to play? have you tried benchmarking using 3dmark03 or 05?

 

[ossycowboy]

I'm gonna try 3d mark 2k5 now. I have tried HL2 /CS:S and Tiger Woods 2005, same thing happens, gonna try more games, although i'm expecting the same thing happening. I was worried it maybe the ocz 520 psu but Hexus did a review running a the same system but with the more powerful ultras on a tagan 480

 

[GuitarDaddy]

Is that OCZ the one with the adjustable power rails? Use ASUSprobe or another utility to check what its putting out on the 12v rail. Maybe one of the adjustments didn't come set right frome the factory?

 

[ossycowboy]

Yeh it is. The psu was the problem, when it overvolts it shuts down. I have now put my tagan 480 in and it seems to be running flawlessly. Thanks for your help - i'm gonna RMA the ocz.
Thing is they cost quite a bit and i'm very disappointed.

 

[bob661]

That's good protection. It shutsdown to keep from frying your components. We had an Antec 550W at work do the same thing.

 

[GuitarDaddy]

Yeah, I use an Antec 550 with adjustable rails. The manual that came with mine says to test the powerrails with a voltmeter before installing. Evidently quite commonly rails get out of adjustment durring pkg'ing/shipping etc.