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PSU not enough? Bad? Amp question related to video card.

Ok so after my 8800gt burnt out after about 2 years or so of use I just put it a 250gts. I've experience the same problem with both cards where when I play games the system will completely shut off, sometimes within the first few seconds. Its not from overheating. The only way I have found to counter it is to underclock the video card by a lot. Now I can still play games fine with it underclocked but would nice to not have to.

This leads me to think its the PSU not putting out enough or its a POS.

PSU zephyr-650 yeah not exactly top tier brand I know.
http://hecgroupusa.com/products/switching-power-supply/retail-power-supply/zephyr-650/

Card 250gts
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127495&cm_re=gts_250-_-14-127-495-_-Product

other stuff
q6600
antec 900
4 gig ram

Ok the PSU is rated 576w max?(says on the side) for the 4-12v rails. Now im not sure im doing this right but that means I have max 48amps.

The video card only has 1 power connector, and it needs a minimum PSU of 450w with a minimum 12v current rating of 24amps.

Now heres where I'm not sure about, each 12v rail is rated at 18amps, but I don't use that when fiquring if its enough, I use the 48 available amps right which means it should be enough?

Maybe something is wrong with the PSU, like not putting out enough clean power?

Thanks for any help, system still runs great besides this issue.
11 answers Last reply Best Answer
More about enough question related video card
  1. Zephyr psu's are POS.
  2. Best answer
    yan66 said:

    The video card only has 1 power connector, and it needs a minimum PSU of 450w with a minimum 12v current rating of 24amps.

    Now heres where I'm not sure about, each 12v rail is rated at 18amps, but I don't use that when fiquring if its enough, I use the 48 available amps right which means it should be enough?
    You're correct.

    Nice job troubleshooting too. That under-underclocking test is pointing at a power problem.
    The GTS 250 is getting up to 75watts (6.25Amps) through the PCI-e slot and up to another 75watts through the PCI-e 6pin power adapter which should be plenty. Either the power supply is having a problem or the PCI-e slot might be having a problem delivering getting the power to the card.

    What motherboard are you using? We can check and see if there is any history of this type of PCI-e slot problem.
    If not your PSU is the prime suspect.
  3. Thanks for the fast replies yeah I forgot to include motherboard is MSI p7n platinum... I'll have to research some more.

    Only other PSU I could hook up is a dell 375w but Im not sure if it has enough power.
  4. I know for certain that Dell 375W PSUs will handle a GTX 260 and Q6600.
    I think it would be safe to use for a test.
  5. lol well sure enough its the PSU thanks again for posting, kind of funny this dell 375 will power it and the hec 650 with all the cords and stuff it has won't... maybe it was just a bad psu but will be the last time I will buy that brand. I would have probly just used the dell but the damn main cord is too short, lol its all ghetto rigged.

    Can't afford a new PS guess I'll have to settle for underclocked, but at least I finally know what it is.
  6. It's also possible the PSU went bad over time. It had a ... 1 year warranty Im guessing?

    I'd go ahead and test to see if the GTS 250 will run OK at it's stock speed.
    If that works you might even try a mild overclock.
  7. the PSU has 4 12volt rails, you need to identify and seperate them so nothing else is on the rail the video card uses.
  8. Yeah I've tried every config I can think of, I just think there is something physically wrong with it, since the day I built it its been the same thing. There are 2-6 plug connector on one rail and one on another rail I've tried all three on the video card eliminating all non essential things on everything else.

    Well at least I can play starcraft 2 on high even without framrate lag even when its underclocked thats all I really care about.
  9. Best answer selected by yan66.
  10. the amps needed is listed on the card and the amps available is lested under your power supply under the 12vdc+ amp output.
  11. This topic has been closed by Mousemonkey
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