Quote:
Originally Posted by Squall-Leonhart
I will correct that sentence for you
The reason i use the word systems, is because it is the overall system that requires the power, in reality the video card only needs about 5-10amps..
|
correct with the theory, but your numbers are wrong. a single 8800 will require anywhere from 7 to 15amps or so at stock speeds depending on the card. an 8800 gtx ultra being the most power hungry single gpu card.a regular 8800gtx will use about 170w at stock, putting it right around 14amps.
Quote:
And most psu's are split rail these days so 18a on each rail is good to have.
personally i prefer the Thermaltake toughpower range, the 600+ have 4 12v rails
|
they arent, actually. at least not in the power range you are talking about. most of them have single 12v rails like my corsair HX620, which is easily the best psu in its class.
Quote:
|
Originally Posted by cid highwind
Well be glad about it.... Because if you use only half the power, your efficiency goes down as well. Usually between 70 and 90% of your max output the efficiency is best. So you just got an overpowered PSU that doesn't fit your needs, so you'll end up using more power than needed.
|
we're talking about a couple of percent at the most here. these days psu's are capable of >80% efficiency right from 20% output up to 100%. it used to be the case where psu's were very poor at low outputs, and still is with some cheap (nasty) brands. but a quality psu will not have that problem
these links are for anybody who needs to know more about psu efficiency.:
Overclock3D.Net :: Review :: Corsair HX620 620w Modular PSU :: Testing 200w load - 80% efficient. 646w load - 83.4% efficient.
JonnyGURU.com - Power Supply Reviews and more! - Reviews - Corsair HX520W 520W 252w load - 82% efficient, 522w load - 81% efficiant
Corsair HX620W Power Supply Review | Hardware Secrets 128w load - 85.9% efficient. 618w load 82.9% efficient.
i left this one for last. get this:
746w load - 82.6% efficiant :
Corsair HX620W Power Supply Review | Hardware Secrets (cont., extreme load test) thats a 620w HX pulling 900w from the mains lol
so, this practice of recommending a psu in the power range for the job is futile. get the best built psu you can for your money and in that case, a 5 year garanteed corsair HX is the best of the bunch. it'll handle sli 8800gtx's, in fact it'll handle anything outside of a 9800gx2 quad setup im sure.
one more thing - psu calculators are trash as well. avoid them.