TWO eVGA 7800 GT's --- Which Power supply to use?

CrispyGordida

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Jan 9, 2006
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MSI K8N SLI 1GHz FSB
AMD Athlon 64 3200+
Corsair 1GB (2 512 pc3200 ddr 400)
eVGA GeForce 7800 GT 256MB
250GB Western Digital Caviar 7200 SATA 3.0Gb/s
Lite-On E-IDE DVD Burner
CoolMax "SLI" CXI-500B v2.01 500W Power Supply
WindowsXP Home

Ok, beautiful graphics!! The computer would shut down while playing Quake 4, Quake 3, and half way thru FEAR new game intro.

Used the SLI connector off of the Power Supply to the video card and it was not enough power! Had to use the splitter supplied with the video card and use two 4 pin cables off of the power supply into one SLI power connector.

Ok, what's the problem then? When we get the second 7800 GT, there is not enough cables left to use another splitter for the second card. Ther is another 4pin cable off of the power supply that goes to the Mobo. This is the first time that I've seen this since this is only the first Dual SLI mobo I've worked with.

The 7800 GT Manual recommends at least 20A on both +12V lines. The power supply is 18A on both +12V lines.

I would take this into consideration if you are planning to have dual SLI cards. Has anybody had success with a power supply to two SLI 7800 GT's?

Thanks[/b]
 

DRAGoNX

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I'd say any "good" 500W PSU should be able to power 2x7800GT's. If you want to be anal about it then get the Seasonic S12-600W or the OCZ Powerstream 600W.

But IMO, a 500W FSP should be fine. (and it's cheap, we like cheap)
 

CrispyGordida

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After playing for approx 8-15 minutes with everything in extreme or high, the computer just shuts down. Downloading the newest driver from eVGA now. Everything is running great other than gaming.

Pulled the heat sink off and put on a better layer than stock (arctic silver 5). Temps are now down from 59C under load (stock) to 40C now using arctic silver). Either temp was nothing to worry about but now it's running even cooler.

Video Card is running no higher 41C at any time.

System is a fresh build and minimal software installation. All newest drivers.

Power Supply issues? Going to measure the rails manually with volt meter.

Anybody have any other suggestions before going to a different power supply? Also, thanks for the input on power supplies, would like to hear some more from people already running dual 7800 GT's.

Thanks
 

CrispyGordida

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Thanks for the link, I was actually looking at that power supply. Just a little out of price range. Would really like to have quad rails and also have the cables detachable.
 

conomega

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Of course your total system configuration is going to play a part on how large of a powersupply you need. I have an X2 4400, dual 7800 GT's and 4 Raptor 74G drives using a Seasonic S12 600W and I've had zero issue with power thus far.
 

merc14

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I'd also recommend you consider PC Power and Cooling. They are very pricey but the power is rock solid no matter the load and they last forever.