PSU advice needed

[sibberovski]

I am currently building a pc, and could really use some help regarding the choice of power supply.
Currently, I have a 955 black edition in my box, and thinking of a gpu in the lines of 6870, and I'd prefer a PSU strong enough to power a second card, should I feel the need for it. I have been searching around for a while on the internet, but found no clear guide regarding what exact specs I should look at.
Any help is greatly appreciated.

Ps. I apologize in advance for potentially terrible english, since it's late, and it's not my first language.

 

[geofelt]

PSU requirements are almost entirely determined by the graphics card configuration.
The recommendations assume a normaly configured pc with a few hard drives and dvd's.
The cpu does not change things much, even if overclocked.

AMD suggests a 500w psu for the 6870 and a 600w psu for dual card configurations:
http://www.amd.com/us/products/desktop/graphics/amd-radeon-hd-6000/hd-6870/Pages/amd-radeon-hd-6870-overview.aspx#3

A nvidia card equivalent to the 6870 would be the GTX560ti. It would have a similar power requirement.

 

[cronos177]

Hello,
Actually if your are not planning to crossfire, based on the 955 and the 6870 a quality 550w power supply should do it. Anything from antec, seasonic and Corsair at that wattage level should be just fine. if you need to see an estimate of your system requirements I suggest you visit here: http://extreme.outervision.com/psucalculatorlite.jsphttp://www.newegg.com/Product/Product.aspx?Item=N82E16817139019
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007657%2050001516%20600014021&IsNodeId=1&bop=And&Order=REVIEWS&PageSize=20 anything there
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007657%2050001697%20600014021&IsNodeId=1&name=SeaSonic%20USA all good no worries.

 

[kajabla]

On a single card, 450 would be enough. On two, I'd suggest a good 650.

 

[ko888]

A Radeon HD 6870 has a maximum board power of 151 Watts. This means that the graphics card itself may draw up to 12.6 Amps from the +12 Volt rails of the power supply unit.

For a single Radeon HD 6870 graphics card system AMD recommends a power supply with 500 Watt or greater with a +12 Volt current rating of 24 Amps or greater and with at least two 75W 6-pin PCI Express supplementary power connectors.

For a two Radeon HD 6870 graphics card system in 2-way CrossFireX mode a power supply with 600 Watts or greater with a +12 Volt current rating of 37 Amps or greater and with at least four 75W 6-pin PCI Express supplementary power connectors is recommended.

Finding a power supply unit with four PCI Express supplementary power connectors requires you to look at reputable brand power supplies starting at 650 Watts and greater.