Core i7 with SLI - only using 550W?

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night_2004

2[H]4U
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May 31, 2007
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Alright, I'm trying to come to grips with this and make sure my 750W PSU is going to be enough for this system.

Antec 300
Core i7 920
ASUS P6T Deluxe V2
2x 750GB WD Caviar Blacks in RAID1
1x 1TB WD Caviar Green
2x GTX 275
(old) Creative XtremeGamer PCI Sound card
(old) Hauppauge HVR 2250 PCIe TV tuner.
Corsair 750W (750TX)

I've run a full stress test on this machine (3dMark Vantage, HD Tune drive scan for both volumes, wPrime to stress the CPU to 100%). According to the UPS I have, the system is only drawing 550W at peak load.

I'd like to think that is realistic, but when nVidia claims the GTX 275 can use up to 219W each and I know the Core i7 is drawing near 100-130W during operation, I want to do a sanity check because I am not sure how much more power the rest of the system needs.

So does anyone else have a similar setup? Are you getting roughly the same figures?
 
I highly doubt that system is drawing 550W at full load. Nevertheless, a PSU is most efficient when it is being utilized at 40-60% of its rated capacity.
 
night_2004 said:
According to the UPS I have, the system is only drawing 550W at peak load.
Click to expand...
550W AC x 0.8 (PSU eficiency) = 440W DC

During simulated games one GTX275 needs ~140W, so 280W from GPU's, 100W from CPU OC'ed and 60W for MB/HDD's/DVD/PCI cards/fans.
Looks pretty normal to me. :)
 
Here's another review that highlights the GTX 275's power consumption. Their test system used 311W at load, and 174W at idle. Factor in idle power...

Maybe buying a Kill-A-Watt would be a good idea?
 
magic_rat03 said:
That calculator gives 620 watts at 100% CPU/100% System Load and I added 2 optical drives and 5 - 120mm high performance fans in addition to his list of components.
Click to expand...

I factored in the i7 920 OC'ed to 4Ghz @ 1.3 vcore. That's why.
 
Calculators give you a ballpark figure, but you should never accept their numbers as 100% trustworthy. In practice, power consumption figures can vary a lot depending on what you are actually doing. At no point in a realistic scenario will all components be drawing 100%, unless you're actually forcing them to do it.
 
Well, for what it is worth my system is stable and I have not had any problems even during long game sessions.
 
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