PSU confusion

By BlindObject
Jun 25, 2007
Topic Status:
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  1. Alright, so I'm sure some are aware I've been wandering around looking for stuff for my computer.

    And I know what I need, but i've come to the part where I dont know what to get.

    I've been searching NewEgg for PSU's that are in the range of 50-60 dollars that has at least 450W and 32 amps on the 12V

    Now, some of them seem sot have 2x 12v's which are 18a each, and I dont know if that's good for my upcoming video card. The requirements for it are 450W and 32A on the 12V. I've found one that has 34A on the 12V somewhere, but I cant find it, I do see alot of PSU with 2 12vs with weaker Amps.

    Do I add both 12v's? For example.This PSU that I found has:

    +3.3V@30A, +5V@50A, +12V1@18A, +12V2@18A, -12V@1A, +5VSB@2.5A

    Does that mean 36A in total?? And can somebody give me a good explanation on Rails and Amps and PSUs in general?



    EDIT:

    I found the one I wanted, but i still want a lesson or explanation on the different between 2 rails and one. What's better and what's not. etc. This is what i was looking for.
  2. Boogityboo04

    Boogityboo04 Newcomer, in training Posts: 351

    I don't really have time to explain about rails right now, but I will recommend that you not get that PSU. Spend $20 more and get a PSU from a reputable brand. No matter how powerful they say it is, it probably won't last long if its cheap.
  3. BlindObject

    BlindObject Newcomer, in training Topic Starter Posts: 446

  4. BlindObject

    BlindObject Newcomer, in training Topic Starter Posts: 446

    I really need this guys :'(
  5. Grafficks

    Grafficks Newcomer, in training Posts: 454

    Yes, 18A + 18A is 36A in total.
    The idea of having dual +12V rails in a PSU was good because it more effectively distributes the power. There are many power-hungry components to a PC, and having them all hog the same +12V rail was not efficient. With dual rails (or triple, even quad), the power is split to each of the components. For example, one of them supplies power to the CPU, while the other powers the video card.

    However, controversy erupted about this using multiple +12V rails in a PSU, and now we have the PSU industry leader, PC Power & Cooling, setting a new standard and ditching the dual-rail PSU design.

    They explain it better than me..
    Go here and read #8:
    http://www.pcpower.com/technology/myths/


    And as for that PSU you linked to, I would suggest staying away from Apevia (Aspire) PSU's. They are on the "Bad" list of PSU brands. The good PSU manufacturers include Antec, Enermax, Thermaltake, OCZ/PC Power&Cooling, Seasonic, and FSP, to name a few.
  6. BlindObject

    BlindObject Newcomer, in training Topic Starter Posts: 446

    Awesome, but would my video card get enough power with a dual 12v rail?

    my newly video card coming is a ATI radeon x1950gt...
  7. dustin_ds3000

    dustin_ds3000 TechSpot Chancellor Posts: 1,128

    u should get a PSU with Modular Cabling if your going to spend over $60
  8. BlindObject

    BlindObject Newcomer, in training Topic Starter Posts: 446

    I think 60 is my tops.
  9. dustin_ds3000

    dustin_ds3000 TechSpot Chancellor Posts: 1,128

  10. kpo6969

    kpo6969 TechSpot Maniac Posts: 875

    WRONG! WRONG! WRONG!
    That psu is only 23amps. Do yourself a favor and read this and look at the chart:
    http://forums.guru3d.com/showthread.php?t=205763
    I don't think your going to find a 32amp psu in your price range, but good luck!
  11. kpo6969

    kpo6969 TechSpot Maniac Posts: 875

     
  12. BlindObject

    BlindObject Newcomer, in training Topic Starter Posts: 446

    23? Where did you get that from?

    Output:

    +3.3V@28A, +5V@30A, +12V@34A, -5V@0.3A, -12V@0.8A, +5VSB@2A

    Also, that chart is very helpful, I'll be researching it...alot.

    Also, I dont understand WHERE each rail is. For example what voltage is the 4pin molex? How do I indentify each one?

    Here guys, this is the video card.

    [​IMG]

    Do you see how it has 2x 4 molex? Would i be able to put any 4pin in there?
  13. Grafficks

    Grafficks Newcomer, in training Posts: 454

    Oh I see...

    You take the the wattage output of all the +12V rails combined, and divide that by 12 for the real amperage..
    Thanks for that useful link, kpo6969.

    BlindObject,
    As listed in that link, that Apevia Concord ATX-MR500W you linked to indeed only has 23A when the correct calculations are done.
  14. BlindObject

    BlindObject Newcomer, in training Topic Starter Posts: 446

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