Dimensioning a new PSU correctly

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How can I check if my system needs more PSU power?

Right now I am shopping for new computer parts. I desperately need a quad core, the dual core gets overloaded pretty quick when I try to livestream while gaming.

So I've come together with this combination:

ASUS P8H67 Rev 3.0, Sockel 1155, ATX, DDR3 4GB Corsair Valueselect DDR3-1333 CL9 x 4 = 16 gb RAM Intel Core i5-2500 Box, LGA1155

I am going to keep my current graphics card, which is:

ATI Radeon HD5770, 1 GB RAM

Also I have two hard drives, a DVD burner and a lot of USB devices attached. I also have an internal TV-tuner-card.

It should be noted that I may put my old Radeon HD3850 into the PC too. Not for the sake of crossfire, but for the sake of trying out BeTwin (www.thinsoftinc.com). Also the reason why 16 GB of RAM. I want to try if two guys can game on one PC with BeTwin. Most games only use two cores so that could maybe work (I tried it on a Windows XP machine a few years ago and it worked great).

My current Coolermaster PSU seems to be dying (crashes, when I attach the power of an E-Sata drive powered by the PC the PC turns off instantly, etc) which is why I'll need a new one.

But I don't know what kind of PSU I'll need for the requirements stated above. How many watts will I need? Also how many ampers of 12v, which is important afaik, will I need?

Thanks for your answers

power-supply

sinni800

Posted 2011-04-20T18:50:52.313

Reputation: 3 048

Answers

The core i5 is a pretty efficient processor, so the Radeons will be drawing most of the power. Pretty much any 500+ watt supply will do just fine. Just make sure it has two of the pcie power connectors for the video cards.

I have a core i5 2500K in an Asus P8P67 Pro with a Radeon HD 3850 and and it usually draws 130-240 watts ( idle-load ). I have a Corsair 550 watt supply and am not sure, but I think it did have the second pcie power connector for another video card.

psusi

Posted 2011-04-20T18:50:52.313

Reputation: 7 195

Alright, I'll check for 550 watts of power... Thanks a lot. You answered with experience though, so I'll check your answer :) – sinni800 – 2011-04-20T19:36:29.173

You should have a play with this:

http://extreme.outervision.com/psucalculatorlite.jsp

That should give you an idea of how much power you'll need - then you can buy the next most powerful power supply - best to be on the safe side...

Majenko

Posted 2011-04-20T18:50:52.313

Reputation: 29 007

Oh wow, why didn't I find this on Google? Thanks, I'll check it out – sinni800 – 2011-04-20T18:59:03.467

Okay, so it recommended 506 watts with a 20% wear. 550 watts should be safe? Should I go for 80plus or is a little lower effectiveness calculated there? – sinni800 – 2011-04-20T19:05:48.720

1@sinni800, You should go for as high efficiency as you can afford. The watts shown are DC; AC usage will be higher due to efficiency. I would advise getting one from a reputable brand, like Seasonic, Corsair, Silverstone, Antec, and there are others. – Mircea Chirea – 2011-04-20T20:23:03.907

Sorry for answering late, but thanks a lot. I have one with 86% efficiency here, a ModXStream. Tests say it's pretty good overall, and it's cheap. – sinni800 – 2011-04-28T15:34:31.890