when i plug in the gpu, cpu doesn't respond

January 18, 2011 at 09:20:56
Specs: Windows 7
Today i built up my computer.
phenom II x4 955
powercolor 5850 pcs+
asus m4a79xtd evo
ocz fatality 550w
dvd-rom 500gb hd502hj etc...

are the specs. But when i started the computer only the cpu fan and gpu fan was running and there wasn't any sign that the cpu was running. After I take out the gpu everything seemed fine. But my mobo doesn't have any onboard gpu so i cannot use my desktop and it freaks me out. I'm suspecting the psu but it should be well enough i guess with 2x12v @25a. Can anybody help me out??

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January 18, 2011 at 09:28:38
I had a similar problem recently with a new nVidia card. Turned out to be a faulty card. I'd have a word with the supplier and see what they suggest.

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January 18, 2011 at 09:35:28
Without stating the obvious, have you plugged in the 2 6 pin connectors?

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January 18, 2011 at 09:37:41
Yep the external 2 6pin connectors were plugged in. When i take off one of them though cpu starts to run again.

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Related Solutions

January 18, 2011 at 10:38:05
Once again, another "builder" who doesn't know how to benchtest:

How to Bench Test Your System

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January 18, 2011 at 13:24:04
ATX mboards are always powered in some places, including some of the contacts in the ram and card slots, even when the computer is not running, as long as the ATX PS is connected to it and the PS is receiving live AC.
Did you make sure you unplugged the power supply, or otherwise switched off the AC power to the computer, at ALL times, when you were fiddling with connections to the mboard and plugging in and unplugging cards inside the case ?

If you didn't do that at ALL times, you may have damaged the video card !

In that case, it won't work with ANY computer that has at least a 500 watt power supply.

BEFORE you try to boot the computer .........
Make sure that the video card is all the way down in it's slot, and that the bracket on one end of it is attached to the case. Some PCI-E X 16 slots also have a sliding piece that locks down the card at the inner end of the slot - use that if it has that.
If the card was / is not fastened down when the power supply has live AC power, merely plugging in the monitor's video cable can cause it to move upwards in it's slot and fry the card, and possibly the PCI-E X16 slot circuits too.

I'm assuming you have it plugged into the first PCI-E X 16 slot, the one closest to the center of the mboard. It may not work in the other slot unless there is a card in the first slot.

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January 18, 2011 at 16:22:28
actually, before i started up the computer first time everything was in place. I controlled several times if the connections were plugged in safely before i opened up I/O switch on the psu. Then i tried couple more times unplugging and plugging dvd, hdd, gpu and rams. I also accidentally broke the pci-e slot locker. Normally, i need to plug 2 pcie external cables coming from the psu to the gpu but even when i take one of them out, the cpu fan runs great so does the gpu fan. I believe it is a power issue related or something else i don't know... It just freaks me out not to use a computer that i've been trying to build for decades.

Sorry for the grammatical mistakes btw. Not a native speaker.

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January 18, 2011 at 18:57:05
Use a free online translator if you need to.
This one seems to be good:

The HD 5850 requires that the system has a minimum 500 watt power supply, or 600 watts for two of them.
I could not find a minimum current rating for one, but several "hits" say you need a minimum 40A at 12v for two, so 100 watts (A x V) difference divided by 12v = 8.33A ; 40 - 8.33 = a minimum 31.67A for a system with one HD 5850.
Your PS puts out 25A X 2 = 50A at 12v - that's a lot more than enough, assuming there's nothing wrong with the power supply.

If you can,
- try the HD 5850 with another system that has at least a 500 watt power supply. If it doesn't work with that system either, the video card is either defective or damaged.
- or - try your system with the HD 5850 in it with a different power supply that has at least a 500 watt power supply - if the card works fine, the OCZ power supply is defective or damaged.

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