What PSU will i need?

I have a ATI 5870 and i'm planning on getting a 5970. I'm going to crossfire the 5870 and 5970 together and was wondering what Wattage PSU i'll need? (i currently have a corsair 650w tx)

thanks!
5 answers Last reply
More about what need
  1. HD5870 (2x6pin + PCI-E lane = 225W), HD5970 (1x 6pin, 1x8pin, PCI-E lane = 300W)

    Plan on at least 500watts dedicated to the graphics cards.

    CPU -> 140 Watts (you WILL be overclocking, no exceptions.)
    HDD -> 15watts each
    Fans -> 1watt each
  2. 850W is the recommended minimum PSU for dual 5970's. Its safe to say it will handle a 5870 + 5970. Go with a trusted brand (Antec, Thermaltake, Corsair, Seasonic ....)
  3. A good 750W will work. OCZ, Corsair, etc.
  4. each 5870 has about a 150watt max load. 5970 is two of those, plus your 5870 means 3. So atleast 450watts right there. plus the rest of your system, another 300-400 watts. I would go 850watt, but if you only plan on using the 5970, then a 750 should be fine. Really, the only thing that scales well is power consumption, the performance increase per card goes down the crapper after 2 cards(aka single 5970). I'd stick with only the 5970.

    be careful about thermaltake
    http://www.hardwaresecrets.com/article/902/7

    750 thermaltake that's worth ~$100. It failed horribly. had 150mv of noise at 80% load, 200mv noise at 100% load and died within a few minutes at 100% load.

    Makes your question their quality checks to sell a device this flawed. This reviewer even got a second unit thinking the first the flawed and had the EXACT same results.
  5. Here are the official power requirements for ATI Radeon™ HD 5970 video card.


    ATI Radeon™ HD5970 System Requirements:

    PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard

    650 Watt or greater power supply with one 75 watt, 6-pin and one 150 watt, 8-pin PCI Express® power connectors

    850 Watt or greater power supply with two 75 watt 6-pin, and two 150 watt, 8-pin, PCI Express connectors for ATI CrossFireX™ technology in dual mode


    The power supply recommendations are for an entire pc system.

    Corsair and Seasonic are two of the brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty. Some of the newer models come with a 7 year warranty.
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