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hardnrg

Actual Power Consumption Of Dual Core + Sli

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I am currently trying to resolve a slightly annoying high pitched electronic squeal from my psu under SLI load (it's definitely from the psu as i used a microphone as a sonic test-probe). I measured the wattage consumption under various states out of interest and thought I'd post up the results as a reference for anyone wondering about power needs for a possible similar setup:

 

Essential Rig specs

 

Opteron 170 (Denmark/Toledo) @ 9 x 315 = 2835 MHz, 1.632v cpu-z (about 1.68-1.69v measured at socket)

2x 7800GT @ 540 (+40) / 1270, 1.71v gpu, 2.35v gddr

 

5 hard drives, 1 optical, 4 panaflo 120mm, 1 delta 120mm, 1 panaflo 92mm

 

rest of specs in sig, this isn't even my whole rig, i'm missing the side panel fans, and ccfls, the cd-rw, fan controller, rad intake fans, etc

 

Results

 

04sliloadvq2.jpg

  • 235 W (idle)
  • 356 W (cpu @ 100%, both cores at full load)
  • 435 W (cpu @ 50%, gpu1 @ 100% - single cpu app, non-sli)
  • 537 W (cpu @ 100%, gpu1 & gpu2 @ 100% - multi-cpu app with SLI)

notice the big jump from idle to load! 121 watts more... and 537 W at full system load is almost worrying seeing as i don't even have everything in the rig yet, even though i have a pcp&c psu

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Sounds like the psu is at it's limit :(

It's a good excuse to upgrade to a 1 kilowatt psu :P

Edited by Celcius

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pcp&c underrate their psu's... mine is rated at 510 W @ 50

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your forggetting the efficiency rating

 

your measuring the AC watts, and when converting AC to DC, you lose wattage, (Hence the "efficiency" rating)

 

so 85% of that rating is about 456 watts (DC wattage, and the psu is rated on its DC power) :P so your close, but not close enough :P

 

EDIT: lol, looks like i was wrong, the efficiency rating on that thing is at 75%, so its more like 405watts max, :P

Edited by The Unforgivin

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whats even more alarming is those goofy looking power outlets you have there :P

they might look "goofy" and really hurt your foot when you stand on an upturned plug barefoot, but these babies give 3.1kW each (obviously not EACH on my surge protected extension lol) but each wall socket

 

you cannot bend the pins anywhere near as easily as american plugs, some of yours are like tin foil i swear lol... ours are like trying to bend a bolt, yeah it's possible, but not without a crazy amount of force like a lump hammer

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they might look "goofy" and really hurt your foot when you stand on an upturned plug barefoot, but these babies give 3.1kW each (obviously not EACH on my surge protected extension lol) but each wall socket

 

:blink: crazyness

 

you cannot bend the pins anywhere near as easily as american plugs, some of yours are like tin foil i swear lol... ours are like trying to bend a bolt, yeah it's possible, but not without a crazy amount of force like a lump hammer

 

:withstupid::bah:

 

i know what you mean....ours are so flimsy

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Our's do have the advantage of taking up much less space! :)

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Our's do have the advantage of taking up much less space! :)

 

well, UK plugs are designed to be much safer... but at the end of the day it's a plug...get over it...

 

it's getting crazy these days...nearly 2/3 of a kilowatt to power a PC ?! soon it will cost more to run your computer than that of your car i swear :lol:

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your forggetting the efficiency rating

 

your measuring the AC watts, and when converting AC to DC, you lose wattage, (Hence the "efficiency" rating)

 

so 85% of that rating is about 456 watts (DC wattage, and the psu is rated on its DC power) :P so your close, but not close enough :P

 

EDIT: lol, looks like i was wrong, the efficiency rating on that thing is at 75%, so its more like 405watts max, :P

 

He is absolutely right.

 

Wattage meters are handly (I have a Kill-A-Watt myself) but the meters only measure AC draw, not DC power draw. The highest PSU AC to DC efficiency I have seen is around 83-85%, and that PC P&C PSU is nowhere near 80% efficient, so around 75% is a good number to go by.

 

So.... 537 watts AC X 75% efficiency (or 537 X 0.75) = ~402 watts DC

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