I am building a new computer soon as my current system is starting to age and i already have the case, motherboard, cpu cooler, neons, dvd writer, hard drive and ram. I plan to get two ATI Radeon HD 6870 video cards and run them in crossfire. I am thinking of getting the Corsair HX650w power supply but im wondering if it will be enough to power this system. So would this PSU power it fine, or will it be best to step up to the HX750?
I also plan to overclock this system as much as i can and it will also have 2 sets on neons in it. 2 blue ones and 2 red ones.
The final specs of the PC will be:
AMD Phenom II x4 955 CPU
Gigabyte GA-890GPA-UD3H Motherboard
4GB Kingston HyperX DDR3 1600 RAM
Samsung SpinPoint F3 1TB
2x HIS Radeon HD 6870
NZXT M59 Case.
Try this link: http://www.antec.outervision.com/PSUEngine , Input your PC info and see how many watts it recommends. The 6850's are not listed yet as the are so new, I used X-Fire 5850's which draw more power just to be safe.
I used high end desktop, your CPU, RAM, 1 DVD rw Drive, HDD, soundcard, 4 USB's, 4 Colc Cathodes, 4 120mm fans, 20% cap aging. That is with no OC keep in mind as I dont know the numbers to enter, so you will be higher than the reading below.
And got 596w so you should be OK with the Corsair 650w, they are usally underated from the amount of power they really can provide. Now if the 750w isnt much more go with that just for extra headroom.
A 650 watt Corsair will be adequate to power a pair of 6870's.
A 650 watt Corsair is rated at about 50 amps. A pair of 6870's will pull 20 - 25 amps. The CPU around 12 amps. That's no more than about 420 watts for the main power consuming components, leaving about 230 watts (plenty) for everything else.