Upgrading PSU, need advice

By Gamree
Sep 16, 2007
  1. Well, first off, I'm upgrading the video card in my current computer to this:

    Problem is, my current PSU (250W, 14A on the +12V) isn't nearly powerful enough to power this card. I know very little about PSU's, so I was hoping someone could make some suggestions as to some good PSU choices. I'm trying to save my money, though, so the best PSU for the cheapest price that could run this card and my computer would be appreciated.

    My PC:

    If I'm missing anything, tell me, and I'll post more info.
  2. Rik

    Rik Banned Posts: 3,814

    Spend as much as you can afford on a psu of 400 watts or better.
  3. kpo6969

    kpo6969 TS Maniac Posts: 710

  4. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    You have the required slots and space IMO for the graphics card. But that PSU recommended by kpo6969 will not cut it, since the card needs 30A on the +12V rail, and the PSU has only 33A. 3A will not be enough for the rest of your system. This PSU on the other hand is much better. It's from a reliable manufacturer and has a single massive +12V rail with 41A on it, which is more than enough for your whole system.
  5. Gamree

    Gamree TS Rookie Topic Starter Posts: 38

  6. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    22A on both rails doesn't really mean a total output of 44A. The real number of total amps will be much lower because all the wattage is not going to be available only on the +12V rails. That amperage rating is the maximum amps available on either rail at a given time. The wattage of the PSU will make a difference as to how much power is available on each rail. But it doesn't always hold. A 450W PSU may deliver 300W on the +12V rail and the rest may be distributed evenly among the +3.3V and +5V rails. Another 450W PSU may deliver equal amounts of wattage on all the rails. This is why amperage is so important.
    So, which PSU are you going to get?
  7. kpo6969

    kpo6969 TS Maniac Posts: 710

    I dis-agree. This is the card:

    This is the manufacturer's product info:

    Manufacturer's system requirements:

      System Requirements
    PCI Express based PC is required with one x16 lane graphics slot available on the motherboard
    Connection to the system power supply is required
    450-Watt power supply or greater, 30 Amps, 12 volt rail recommended (assumes fully loaded system)
    512MB of system memory
    Installation softward requires CD-ROM drive
    Operating Systems Support
    1.Windows XP
    2.Windows XP x64 Edition
    3.Windows Media Center Edition 2005
    4.Windows Vista

    My point:
    450-Watt power supply or greater, 30 Amps, 12 volt rail recommended (assumes fully loaded system)

    So your point is if 30 is required 33 isn't enough but 41 is?
  8. kpo6969

    kpo6969 TS Maniac Posts: 710

    Same manufacturer, same psu but more power.
    8 amps = $35.00
    The OP did state they were trying to save money.
  9. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    google a free PSU calculator and add 30% to the results.
  10. James27uk

    James27uk TS Rookie

    With regards to this can I just add a really newbish question the fan on my psu is pointing into the computer and not towards the grill in the main case. Is this correct? the outer panel(detachable) does not have any holes in it to allow air out if the psu was turned over (fan outward at grill). Is there any advantage to be had with turning the psu so the psu fan blows air out rather than onto the cpu heatsink? (even if the outer panel has no vent)
  11. Rik

    Rik Banned Posts: 3,814

    With cooling, because heat rises, it's usually best to have the fan(s) at the bottom of the case pulling air in and the fan(s) at the top pushing air out.
  12. James27uk

    James27uk TS Rookie

    Ok excellent thanks for that I will turn it over later do you think I should modify the outer panel to allow the repostioned fan to blow direct into atmosphere?
  13. Cinders

    Cinders TechSpot Chancellor Posts: 872   +12

    James if you have the skill and don't mind voiding your warranty then have at it. I think it's a good idea. :) Just remember that your PSU can have powerful capacitors that contain very high voltage which can kill you.
  14. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    that is not correct. Proper air flow in a computer dictates exhaust fans on the top and rear and intake fans on the bottom .
  15. Rik

    Rik Banned Posts: 3,814

    What exactly is not correct?
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