Gtx 460 and my 400w PS

Hi all,

I think I am okay but I am seeking others input. I recently added a gtx 460 to my system which Nvidia states it requires a PS with 450w and with +12 Volt current rating of 24 Amps.

My current supply is a ENERMAX Liberty ELT400AWT 400W ATX12V SLI Ready CrossFire Ready (http://www.newegg.com/Product/Product.aspx?Item=N82E16817194002). It is dual 20a rails - +3.3V@26A, +5V@28A, +12V1@20A, +12V2@20A, -12V@0.6A, +5VSB@3A .

I measured from the wall gaming and using furmark. Max draw is around 345watts now. My 8800gt max draw was 233watts. I think I am okay and may remove one of the 3 hard drives in the system.

Any thoughts?
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  1. mbob said:
    Hi all,

    I think I am okay but I am seeking others input. I recently added a gtx 460 to my system which Nvidia states it requires a PS with 450w and with +12 Volt current rating of 24 Amps.

    My current supply is a ENERMAX Liberty ELT400AWT 400W ATX12V SLI Ready CrossFire Ready (http://www.newegg.com/Product/Product.aspx?Item=N82E16817194002). It is dual 20a rails - +3.3V@26A, +5V@28A, +12V1@20A, +12V2@20A, -12V@0.6A, +5VSB@3A .

    I measured from the wall gaming and using furmark. Max draw is around 345watts now. My 8800gt max draw was 233watts. I think I am okay and may remove one of the 3 hard drives in the system.

    Any thoughts?

    If the psu is maintaining 80% efficiency you're under a 75% load when running the power viruses, should be fine.
  2. Yes, Enermax makes quality PSUs so you will be fine.
  3. ct1615 said:
    you will be fine. its an quality PSU with 30a on its 12v rail.


    Where is that in the specs? I only see it has 2 12v 20a rails. I'm curious, being I seem to be under the rating (24a) per the Nvidia spec worries me.
  4. Cool! I did not notice that. Thanks.


    Since I am drawing 350w max load from the wall and the PS is 80% efficient, does this mean I am only drawing 280w out of the supply to my system? That sounds low considering the CPU is a 95w q9550 but maybe it is accurate.
  5. I believe the 95W is max. Which you will probably never see unless you OC...

    And since Furmark barely uses any CPU power, you can try Prime95 and Furmark at the same time, but I don't think that is necessary...
  6. Very helpful info all! I just did another test and measured:


    Idle: 108w
    Prime95: 180w
    Furmark: 340w avg peak 352w
    Both Prime95 and Furmark: 427w

    So the worst case scenerio of max draw at 427w times the 80% efficiency equals 340w. so if I am reading this right then at peak I am within 85% of max 400w. Being that I will rarely peak anything close to that prime95 + furmark test, we are good to go right?

    Thanks for the incredible help.
  7. This is not the worst case scenario if you need all your devices to work at the same time, dvds, raid volumes, external HDs , usb sticks at best PSU isn't really a simple case.

    If you plug your psu to a digital polymeter while you running these tests you may see really big drops in the ambers, volts never a stable line if the minimal values you get can effect the performance of a raid volume you jump to bigger watts psu thinking you be safe in there but finally 80% bronze PSUs can fully cover you how much? It depends on what you have connected or you thinking you will connect in the feature.

    The worst case scenario is the 0 memory test but do it at your own risk. The settings in Prime95 64bits torture custom are in my case was 4096Kbs minimal FFT, 8000 memory usage, if you put all your memory to be used in Prime95 then when it hits 0 free memory in the task manager your will hear the disk to work is the swap file that is so big as the memory you used you will experience problems in cpu usage, you will not be able to give us flat line in task manager, some programs on screen may not updated if you move a window behind will be a hall, in other words your system will get back in ‘stone’ age when we had 4 Mbytes ram and your windows are forced to work in my case 8Gbytes ram +9 Gbytes swap = 17Gbytes with so small space....

    Your systems will fail to provide s screen shot like this:
    http://admins.bnb.gr/~giatrakis/Prime95-torture-8Gbytes-Furmark1.8-extrem.jpg

    My point is I can do even that! It needs expensive hardware, special treatment and in servers even the smallest volt is counted and there is no room for errors. =;-)
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