Is this 400W Enough for a 8800GTX?

By Nirkon
Oct 29, 2007
  1. I have a very good Enermax Liberty 400W power supply.

    I calculated my PSU load here:

    at 100 percent everything (load)!!!!
    and I only needed 346W.

    Will there be any problem running this card with this PSU?

    please help,
  2. Tmagic650

    Tmagic650 TS Ambassador Posts: 17,233   +234

    People always seem to think the more watts the better. Your power supply is fine... use it!
  3. Rilla927

    Rilla927 TS Rookie Posts: 152

    No way would I run this. GTX requirement is a minimum of 450w. See system requirements under specifications tab.

    You have to think about everything else that draws power besides the vid card. What about adding/ upgrading hardware. You need to allow room for that. What are the specs of your whole system?

    You never want to run any system at the bare minimum cuz your asking for trouble. PSU's don't run at 100% efficiency.

    Buy yourself a Corsair and you will have peace of mind and a 5 year warranty.
  4. Nirkon

    Nirkon TS Enthusiast Topic Starter Posts: 202

    I ran it at 80 percent efficiency and ill probably never upgrade anything, but the only thing i'm likely to upgrade is another 2GB ram...

    yeah, ill get the 640 and not the GTX.
    i dont have enough power for it.
    cause i plan to overclock the cpu and that passes the 400 mark.

    thanks guys!
  5. Rilla927

    Rilla927 TS Rookie Posts: 152

  6. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    That Enermax is able to put out a maximum of 30A on the +12V rails combined, which is more than enough for an 8800GTS or even a GTX.
    @Rilla927, the amperage number provided is for a system with that graphics card under maximum load, not idle. So that PSU will do just fine. It's a Crossfire-certified PSU and ATI's cards are always known to draw a lot more power than NVIDIA's, so that itself is a measure of it's superior quality.
  7. Nirkon

    Nirkon TS Enthusiast Topic Starter Posts: 202

  8. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    Absolutely. The 8800GT is the best price vs performance card right now.
  9. pdyckman@comcas

    pdyckman@comcas TS Rookie Posts: 527

    I have read the recent reviews of the 8800 (maybe superclocked, doesn't matter:N'Tune will up the clocks easily anyway). I was happy to see that my 8800 GTS ran in tandem with ALL of the competition: (including Ultras). Nothing beat it by any kind if margin whatsoever. (In all games). I know this sounds amazing...but read PC World's tests. Also...the best way to choose a PSU for a GFX app. is to look at the amperage on 12 volts. The watts = amps x volts. (P=IxE)
  10. Rilla927

    Rilla927 TS Rookie Posts: 152

    Yes, it's capable of running it as a minimum requirement. I never said it couldn't run it, but personally I would never run any system at it's minimum with no head room.
    I'm aware of this.

    Not with these newer cards and he plans to OC, good luck!
  11. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    The minimum amperage required for an 8800GTS-equipped system is 26A, while that for an 8800GTX-equipped one is 28A, so 2A of headroom is more than enough methinks. Of course, I missed the CPU OCing part, so the above information's irrelevant unless he doesn't OC it. ;)
  12. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

    Where did that come from?

    I'm using my factory-overclocked 8800GTS 640M with this 360W PSU.
  13. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,689   +395

    What?! you mean you don't need a 700W PSU to run a C2D and a 8800?


    I've wanted to say from the start of this thread I think you could get by with that 400, but I wasn't sure enough to stick my neck out. I've never seen my system use over 245W according to my Kill-a-Watt meter even under a heavy gaming load.
  14. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    @Miclantecuhtli, that's eVGA's specification for their 8800GTS 640MB. Look here. Oh, and your link doesn't work. But from what I found on another website, your PSU delivers exactly 26A at peak on the +12V rails combined, which is enough for your system.
  15. nickc

    nickc TechSpot Paladin Posts: 923   +11

    Rage, your link does not for work itself. Well you get a link but I do not think it is the place u want to go.
  16. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    Newegg changed the item number for the card. Link fixed.
  17. pdyckman@comcas

    pdyckman@comcas TS Rookie Posts: 527

    I learned something about Zalman products today. That 360 watts is 96% effective (active PFC). That's amazing,plus: between 12v #1 & 12v #2 there are a total of 40 amps. It's not the watts but the amperage when it gets down to it. The power (in watts) =amps x voltage.
  18. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    Just because the two rails are capable of delivering 20A each doesn't mean they deliver 40A together. That means they give an output of about 480W on the +12V rails alone, which is impossible given the total power output of the system. Zalman's page here says it provides a maximum of 312W combined on the +12V rails, which translates into 26A on both rails combined. The Corsair VX550W on the other hand delivers a massive 41A on its single +12V rail and for it's price vs performance ratio, it is arguably the most powerful PSU around, even if it's not modular.
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