Sli Psu

By MetalX
Dec 28, 2006
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  1. I have just recently purchased a 7950GT and an SLI motherboard, and they are great. Now I have realized that I have enough money to buy another 7950GT and put it in SLI. The side of the box (BFG Tech) says I need a 500 watt power supply with 28A on the 12V rail to run SLI 7950GTs. My PSU is an Enermax 460 watt with 33A on the 12V rail. I don't really have much inside my computer, just:

    Overclocked CPU
    Mobo
    2 DDR RAM sticks
    1 HDD
    2 DVD Drives
    Soundblaster Live! 5.1
    a few fans

    Now, I am wondering if my PSU would be adequate for running 2 7950GTs or if I need to get a bigger PSU.
  2. MetalX

    MetalX TechSpot Chancellor Topic Starter Posts: 1,909

    Anyone have any idea if this would work?
  3. Grafficks

    Grafficks Newcomer, in training Posts: 454

    Even though the wattage recommended by BFG is certainly just an estimate, I would certainly heed it's recommendation and upgrade to at least 500 watts of power. Besides, you could use a new PSU with dual rails.

    The 500W power supply recommendation is probably made considering what is inside an average PC. The quantity of devices in your PC is pretty average.

    Dual 7950GT's are two very high-end graphics cards so you will need the extra wattage for sure. Just to be safe, you don't want to have crashes after you add your other 7950GT!!
  4. dmill89

    dmill89 TechSpot Guru Posts: 737

    My personal recomendations would be the PC Power & Cooling Silencer 610 or silencer 750 if you want more wattage(These are avalible at www.pcpowercooling.com and newegg). Two video cards and an overclocked CPU are hard on a PSU so I would definately recomend an upgrade.
  5. MetalX

    MetalX TechSpot Chancellor Topic Starter Posts: 1,909

    Ok, thanks guys, I used the PSU calculator HERE with my exact system except with 2 7950GTs instead of one, and it came up as 405 watts. But, I guess I probably should upgrade to a bigger PSU before going SLI... I guess I won't be able to go SLI till the summer then :(
  6. Tmagic650

    Tmagic650 TS Ambassador Posts: 20,451   +135

    MetalX,
    Your current power supply should work fine. Too many people recommend hugh power supplies, and they don't realize that there are many good 350 to 450 watt supplies that will out perform any 500 to 600 watt expensive beasts. I have an Antec Smart Power 350 watt supply powering 5 hard drives 2 DVD/CD R/W drives and an Intel 2.8GHz Celeron D processor with 2GB Corsair RAM... with no problems
  7. sghiznaneck

    sghiznaneck TechSpot Maniac Posts: 544

    Tmagic650, you're correct.. to a point. The gpu is the biggest hog in the system nowadays. And running a SLI config should have a little extra "head room" for power consumption, especially when running higher end cards.
  8. peterock

    peterock Newcomer, in training Posts: 33

  9. MetalX

    MetalX TechSpot Chancellor Topic Starter Posts: 1,909

    Well, I won't be getting SLI anytime soon after all... I just went out and spent $135 on OCZ Premier Series PC3200 1GB Dual channel kit, and $40 on Zalman 7000 (all CAD), so I don't have money for a new GPU anyway... but thanks guys.
  10. sghiznaneck

    sghiznaneck TechSpot Maniac Posts: 544

    I've never heard of Hiper psu's. I can only speak from experience. Antec, Thermaltake or Ultra are all good brands, and modular is definitely the way to go. I own this one (Ultra 700 watt XVS)

    http://www.tigerdirect.com/applications/Category/category_tlc.asp?CatId=106

    It's a little pricey, but when it comes to power and my recent build, I'd rather be safe then sorry. The modular cables are a breeze to connect and the airflow IS much better inside the case. But, in the end, it's your decision.
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