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300 watt power supply enough??

Discussion in 'Nvidia' started by BIGMIKE, May 9, 2007.


    BIGMIKE Guest

    I'm looking to upgrade my video card but many of the Nvidia cards require at
    least a 350 watt power supply. In my HP computer it has just a 300 watt
    power supply. What would happen if I insalled a card that needed 350 watts
    I only have 300? Would the card or computer get fried or blown up? Thanks
    very much!!
    BIGMIKE, May 9, 2007
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    Paul Guest

    If you examine the label on the side of the supply, you'll find there
    is more to it than some "total power" rating. Each individual DC output
    has a rating too.

    You can work out, after a fashion, how much 12V your computer uses.
    On modern systems, the majority of the loading is on the 12V rail.
    So the rating of the 12V rail may be crucial to deciding whether
    a new toy can be added to the computer or not.

    Xbitlabs has measured a number of actual video cards, and you can get
    numbers for the DC current flow of the video card from there.

    Since you provide no particulars for your problem, like a complete
    hardware inventory, what old and new video card is being used,
    it is hard to advise further.

    In terms of the consequences of overloading a supply.

    1) Cheap supplies and quality supplies may differ in the
    degree of protection afforded, in the event of a failure.
    2) Supplies have thermal protection. When they get too hot,
    they may shut off. Exceeding the total power or individual
    ratings, could cause it to overheat.
    3) If the DC rating of a rail is exceeded, generally it takes
    a 30% overload, before the overcurrent circuit shuts off the
    supply. If the supply had 12V @ 10A, and you drew 13A from it,
    the overcurrent might decide to trip.

    (2) or (3) cause no damage.

    If the supply output voltage starts to drop, the computer could crash
    in response. So you don't always get a neat and tidy sudden switchoff.
    Maybe you see instability instead.

    Really cheap supplies can pop, belch smoke, and actually take
    out the motherboard when they fail. A cheap supply may not have
    the necessary protection features.

    A company like HP is probably more concerned about class action
    suits, and litigious customers. So maybe their stuff won't
    disappear in a cloud of smoke.

    Paul, May 9, 2007
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    don't look Guest

    Wolrst that would happen is you get a message telling not enough power or
    you'll get freezing.
    don't look, May 10, 2007

    Charlie Guest

    Adequately sized supplies are inexpensive so spend a couple bucks and get a
    supply rated for the task at hand.
    -ps some PC's do not use standard ATX-type supplies (like some Dells) so
    make sure
    the new supply is the right configuration for your particular pc's chassis
    mounting and AC plug location
    Charlie, May 10, 2007

    Roger (K8RI) Guest

    On Wed, 09 May 2007 23:07:23 GMT, "don't look" <don't
    Even good supplies don't always fail nice.
    I overloaded one (400 watts) that was supposed to be good quality and
    the only thing left on the motherboard still good was the RAM.

    Conversely I had one fail multiple times until I discovered the
    problem was one of the fans. I also found in one instance I was
    running so near the edge adding one case fan was the difference
    between running and not running. The extra load of that one fan
    (which aint much) on that rail was enough to prevent the computer
    from even starting.
    Roger (K8RI), May 10, 2007

    art critic Guest

    Depends which Hp you have. A friend of mine has some gawd awful HP
    son of satan product that craps out if you even put in more memory.

    It was some kind of art project for an Hp engineer on cocaine.

    Hey I guess you don't read the business section, but HP is not the
    kind of product you want to buy.
    art critic, May 10, 2007

    No One Guest

    But the stock is.
    No One, May 10, 2007

    DaveW Guest

    You could very well damage the video card AND many of the other components
    in your system due to the unstable voltages that would result from
    overstraining your PSU. Not a good idea, as they told you.
    DaveW, May 11, 2007

    art critic Guest

    LOL. You were warned ;)
    art critic, May 13, 2007
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