PSU for 580 gtx

bigdaddycoop

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May 27, 2011
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I am about to buy a 580 gtx but dont know if my 600W psu will be enough. Probably not since the min req for this card is 600W.
Anyways, i was wondering how do i find out which psu i will need?
Here are my specs:
i7 950 3.7
6 gb RAM
i hdd and i cd/dvd drive
about to buy 580 gtx (this one is the 3 gb one)
I have 4 or 5 usb spots that are being used.
Hopefully thats enough if anyone needs to ask more questions id be happy to answer them!
Thanks guys
 

ghnader hsmithot

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GeForce GTX 580

On your average system the card requires you to have a 650 Watt power supply unit.
GeForce GTX 580 in SLI

A second card requires you to add another 250 Watts. You need a 900+ Watt power supply unit if you use it in a high-end system (1 KiloWatt recommended if you plan on any overclocking).
http://www.guru3d.com/article/geforce-gtx-580-review/7

I think you would be able to go for a 700w one.
 

cronos177

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Mar 18, 2011
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No need, Let's say a GTX 580 will get a max of 75w from Mobo, another 150w from the 8 pin, let's say another 180w at most from CPU, and peripherals. That worst case scenario 75+150+180= 305 Watts from one rail 305W/12V = 25Amps seems like plenty, Event if you say 400W from one Rail 400/12 = 33.3 Amps out of 38Amps, It is just too much for cheap. Does it make sense?
 

cronos177

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For a single GeForce GTX 580 card system you should be using a power supply with a combined +12 Volt current rating of 42 Amps or greater. If your current 600 Watt power supply unit meets this specification requirement you will be fine. The power supply should also have at least one 6-pin and one 8-pin PCI Express Supplementary power connector.

Two GeForce GTX 580 in SLI mode would require a power supply with a combined +12 Volt current rating of 62 Amps or greater.
 
Just to give you a point of reference, I have a 950TX 80-plus power supply (much more than I need). When I max out gaming with 2 580s in SLI, my measured draw from the outlet (using an appliance load tester) has never exceeded 780W. This is while each GPU was in the high 90%s GPU load as measured by GPUz during gaming.

So let's say, as a worst case scenario, my PSU was operating at exactly 80% efficiency at that load:

780W * .8 = 624W required by my system with 2 GTX 580s almost maxed out. This is with 8 threads working on the CPU while playing BFBC2.

The OC on your CPU increases your power draw on the 12V rail (normal non-OC'd requirement is 10-12.5 Amps), so you have to take that into consideration. The OC could require anywhere up to 8 additional Amps. I would say you'd be OK with a 600W CPU if the 12V rail offered up around 240W (20A) for the CPU and another 240 (20A) for the video card. On top of that, any system fans will draw from the 12V rail as well.

The supply I'd recommend would give a little more than you need on the 12V rail, account for the CPU OC and provide a reliable power solution for years (5-yr warranty):

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020&cm_re=corsair_650w_power_supply-_-17-139-020-_-Product