BleepingComputer.com: Need new PSU for new video cards?

Hello all,

Been thinking on upgrading my video cards for a while as the 8800GT's just aren't cutting it anymore for today's games. Plan to upgrade to 2 GeForce GTX 460 in SLI mode (http://www.newegg.com/Product/Product.aspx?Item=N82E16814130562).

My concern is the power requirements. As of now, I have a 700 watt PSU that has 2 SLI power plugs, but the GTX 460 card uses two of them. I'm aware that the video card comes with a power splitter and I can use my existing PSU SLI plugs for both cards, but will it be enough? I've wishlisted a PSU that I know can handle it fine and has 4 dedicated SLI power plugs (http://www.newegg.com/Product/Product.aspx?Item=N82E16817139009).

I'd rather hold off on the PSU and use the one I have for now until I have the moolah to buy the new PSU (or do I even need it?)

As for the rest of my specs:
Motherboard: EVGA nForce 680i SLI
CPU: Core 2 Duo 2.4ghz overclocked to 3.4ghz
RAM: 6gb Corsair Dominator (slightly underclocked for 1:1 ratio)
OS: Windows 7 64-bit, of course!

Thanks in advance guys.

It would help to know the make and model of your current PSU.

dc3, on 31 December 2010 - 12:19 PM, said:

Ah yes, you'd be right on that, how'd I miss that? No matter, here it is: COOLMAX CUG-700B 700W ATX12V v2.3 SLI Certified / CrossFire Ready Modular Active PFC and Compatible with Core i3/i5/i7 Power Supply. Here's the page on Newegg: http://www.newegg.com/Product/Product.aspx?Item=N82E16817159058&Tpk=17-159-058

Thats a shame as that Coolmax is not a bad power supply (for a Coolmax). It did blow up during testing, but........ http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=68 The problem is it only puts out 500 watts total on the 12V rails, and that will put some strain on it running SLI 460s.

Problem is, each card pulls a max of ~180 watts, plus figure another 100-120 watts for the CPU, and you get real close to 500 watts, or at least what I consider out of the "comfort range" of 60% I adhere to. Notice that the newer upper tier PSUs have almost the total output available on the 12V rail. Example, that 850 Corsair has 840 watts available on the 12V+.

Read that review on JonnyGuru and see what rails are actually available on the Coolmax. If the 12V+ are tied together, then I would give it a shot if money was too tight to get another PSU now. If the rails are actually separate, and have individual current limiting, then I would pony up now and get that new 850 Corsair.

SLI'ed 460s are great performers.

EDIT: Page 3 of that review has a list of the rails/connectors. It seems to be a 2 rail unit, with one rail split into 2 for three total. None of the rails are actually isolated, no overcurrent protection either.

This post has been edited by dpunisher: 31 December 2010 - 05:18 PM

dpunisher, on 31 December 2010 - 05:10 PM, said:

Crud. I was afraid of that. I don't want to take the risk that my current PSU *might* be enough for the 460s in SLI mode, I'd rather plunk down the money on a new PSU that I know for sure can handle it just fine. Guess I know what I'm doing with my tax refund!