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.
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.
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.