New PSU

Discussion in 'General Hardware' started by lblrydr, Mar 25, 2007.

  1. MTL

    MTL Maha Guru

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    GPU:
    EVGA 7900GTO SLI
    No idea Kwak. I don't post here that much but I think I will start posting in this forum a little more.

    Oh and as for the people who are talking about "combined" rail amperages, it is a bunch of hooey. Those figures are just trumpet-up, baseless figures that are spewed by the graphics card manufacturers. They don't take into account peak vs continuous power output, rail distribution, OCP limitation etc, etc.

    I believe that quoting those figures does a great disservice to everyone reading the post.
     
  2. Makalu

    Makalu Ancient Guru

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    GPU:
    EVGA 8800 Ultra
    well Nvidia and ATI and the various GPU retailers try to come up with a figure that they think will work for most people given the variations you mentioned and also variations in individual system configurations. Certainly a stock C2D6300 system with one hard drive and optical drive and a few fans isn't going to need as much as the GPU recommended minimums. And a system with an overclocked Presscott and three hard drives and 2 opticals a few fans and a 12v DC water pump would need significantly more 12v amps then the other configuration even if they do both use the same graphics card. I think the GPU retailers try to come up with a fairly realistic figure somewhere between the two extremes and give themselves a bit of headroom so that they don't get a ton of "you said my psu would work" complaints. But then they are also in the business of selling GPU's and they don't want people to feel that they can't afford to buy their card without buying a bigger psu to power it with too. I reckon that they could care less if a unit is being stressed to near it's max continuous but consumers should be aware that if efficiency and longevity of the unit are important to them then pushing the envelope isn't the best scenario. I suspect that a majority of gamers still think that if they add the individual rail amperages together then that gives them the combined rating...certainly there's some around here who still flaunt the individual rail over current limits in their sigs as if it meant something lol. I don't know if retailers take that common misinterpretation into account but I reckon they have to account for power supplies that are just flat over rated in the total watts department. What I try to do is break down the peak 12v amperages for all the components in a system and add that and even though I know that the system will never ask all of it's components to run at peak levels all at the same time I still consider it a valid figure for leaving overhead for efficiency and longevity and over-rated units and peak vs. continous ratings and all the other things mentioned. And when I do that I usually come up with a figure a bit less than the retailer recommended...then I have to fend off all the people who are convinced I'm wrong and the figure should be higher. lol I think a lot of people just want to believe that their system is "hotter" than it is and that it really requires a lot bigger psu then it really does...so it's a hard balancing act sometimes.
     
    Last edited: Mar 26, 2007
  3. CTman

    CTman Ancient Guru

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    That's why e.g. the "26 amps on the 12V" is a minimum requirement and not a recommended requirement for a pc system with a geforce 8800gts. It's actually quite logical; if you use a more power hungry cpu and a more power hungry videocard (and more "12V" devices/components etc.) you will (automatically) need a more powerful power supply to sustain a stable machine.


    Good luck!
     
  4. Makalu

    Makalu Ancient Guru

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    GPU:
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    I guess I should mention that some of the retailer recommendations for some of their cards are just way out of line...saw one once that recommended 30 amps combined 12v for a card that consumed about 5 amps. And Nvidia sometimes releases power consumption wattage numbers that are about 20-30 watts over what people measure the cards at. The 8800 recommendations sound about right on paper to me though.
     

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