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CPU wont start when I plug my PSU into my GPU.

Hey everyone, I just bought a new radeon 7950 and a new power supply for my pc. I installed the PSU properly, and it boots my computer fine. Next, I inserted my GPU into the PCI-e slot on my motherboard, and when I run the pc, it boots fine and the fans spin on my 7950. The problem is that when I plug my PSU's 6-pin plugs into my graphics card, the fans all start to run, but my CPU doesn't boot. Any idea as to what the issue is? Thanks!
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More about cpu wont start plug psu gpu
  1. What make/model of PSU did you install?
  2. Oh sorry, I forgot to add that:

    CPU: intel i3-2100
    GPU: Powercolor Radeon 7950
    PSU: EVGA 500B Bronze 500 Watt PSU
  3. Have you tried the HD7950 in another computer?
  4. I'm afraid I don't have any computers available that will run the card. It seems to start just fine as the fan is going, and it even runs with only one 6 pin connector, but as soon as I plug two connectors in, my CPU just won't boot.
  5. That would imply a problem with either the PSU or the HD7950.

    Do you have another video card (not the integrated video) that you could install to verify the x16 slot is okay?

    BTW, just because the fans on the HD7950 turn, that doesn't mean that the GPU is 100% operational. It just means that it is getting power.

    The HD7950 does require both PCIe power connections in order to work.
  6. This is my first graphics card, so unfortunately there is very little to troubleshoot with. I noticed that my card does not show up on the device manager. Should it? Or will it only show up when it is connected to the psu?
  7. Is your monitor still connected to your integrated video when the HD7950 is installed?
  8. I've tried it both, connected to the integrated card and to the GPU, but it still gives the same results.
  9. Given this, I suspect that your GPU (the HD7950) is defective.
  10. That's disappointing, should I try having it tested?
  11. Best answer
    If you can find another system to check it in, you can test it yourself. Otherwise, I would return it for exchange where ever you bought it from.
  12. Ok, thank you for your help! At least I know the power supply works. I'll exchange it and hopefully have better luck with the next one. Thanks again!
  13. There is a remote possibility that the PSU is the problem as well. But, the GPU is more likely the issue.

    Please follow up after your exchange.

    Good luck!
  14. I read somewhere that updating the pc's BIOS can sometimes fix this issue for pci-e 3.0 graphics cards. Would you recommend I try that first?
  15. You can certainly check to see if your motherboard has an available BIOS update available. True, there have been some issues in that regard.
  16. Ok, so before I send it in for warrenty, I had a friend try the card on his pc and he just told me that it runs fine with his custom pc and power supply. Any ideas what I should do now? Should I return the card for a less powerful one, or should I try to replace the power supply?
  17. I would suspect your PSU at this point.
  18. Ok, I'll try to get my hands on another GPU in the next couple days and see if I get the same results. Or perhaps purchase a different PSU for the card.
  19. Alright, I've borrowed my friends GTX 550 Ti (Requiring one 6-pin plug in) and tried it with my PC and PSU. This time my pc boots, but I only get display from my onboard graphics. The fans spin on the GPU, but my pc doesn't recognize it, and it's not even in the device manager. Does this help at all?
  20. Nevermind, The card was not inserted all the way. I tried it again and this time the GTX 550 Ti worked fine with my pc. It booted and showed output just like it should. I tried it again with my 7950 and still nothing will boot. Does this mean that I need a more powerful PSU to run the 7950? Or could something else be the problem?
  21. It really sounds like your PSU is not providing enough power to the HD7950.
  22. That's what I was thinking. Looks like I'll have to go pick up a 600w to replace it.
  23. Alright, I just installed a CoolMaster 625w power supply, and I'm still receiving the same the results. The computer just will not boot with those two connectors plugged in. Any ideas?
  24. Still no luck running this card. My computer will not boot no matter what the configuration. Any other suggestions before I resell the card?
  25. What make/model is your motherboard?
  26. Its a Carmel motherboard made by pegatron corp. with Ami 7.13 BIOS it also has two sticks of ram installed.
  27. If this is your motherboard, go to this link:

    Enter the Bus Options settings in your BIOS and ensure that PCI VGA Palette Snooping is enabled. Then save and shutdown.

    Try the HD7950 again.
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