Computer freezes, video signal drops, and GPU fan jumps to max speed.

Help. I just installed a HIS Radeon 7850. The computer is freezing within a minute or two of boot-up, the signal to the display drops, and when that happens the GPU fan goes from normal to 100% speed instantly.

The sordid backstory: First, running an Athlon II X3 @ 3.0 Ghz on an ASUS 890GX motherboard with an XFX 850W power supply. Just upgraded the video card from a Sapphire Radeon 5770. System is almost two years old and has never had any major problems.

I recently decided to unlock the fourth core on the CPU and overclock to 3.5 Ghz with the ASUS automated tools. I did this about two weeks ago when I pulled the 5770. It ran fine at those setting for two weeks. I was using the on-board integrated graphics during that time with updated drivers.

I installed the 7850 this morning with updated drivers. Forgot to plug in the 6-pin auxiliary cable. Wonder why it doesn't work for a while then realize my mistake. Unplug power supply, plug in 6-pin cable, re-connect power supply, boots up just fine. Played Dungeon Defenders for about 10 minutes and then the screen went black, loud buzzing noise, hard crash.

Got an error on re-boot that overclocking and/or unlocking had failed. De-activated the unlocked core. For some reason the computer thought the 3rd core was the unlocked one. Only running two cores at this point.

Re-boot several times. Overclocking error. Re-set bios to defaults. All three healthy cores running. No overclocking. No unlocked fourth core. Re-boot. Computer works for a minute then the screen goes black with a DVI No Signal message. No noises from the computer but I notice the fan is very loud.

Re-boot. Same thing. Realize it's the GPU fan that's going at max speed when the crash happens.

Pull the video card and go back to integrated graphics. Everything works fine.

Re-install video card. Again forget the 6-pin cable (oops). Realize mistake, power off, unplug, and re-connect cable. System boots, then freezes and the GPU fan takes off again.

Pull video card again and switch back to integrated graphics. System hasn't crashed since.

Okay, no idea what's going on with the video card. Did I stress something when I forgot to plug in the 6-pin power connector? Is it just a bad card? Is there a config or BIOS issue I'm missing? I'm pretty sure I'm okay on power as the power supply has never had an issue and is running everything else just fine. Wondering if it's worth putting the card in the other PCI slot to see if that works.
Any thoughts on this? Never encountered this before.
6 answers Last reply Best Answer
More about computer freezes video signal drops jumps speed
  1. sounds like a possible driver issue. run driver cleaner/uninstall all video drivers/devices and then try. Also what OS are you using?
  2. Sorry, Windows 7 64-bit.
  3. Best answer
    bodmatt said:
    Sorry, Windows 7 64-bit.

    k. should be fine then. as long as its not XP.

    I don't suppose you have another system or a friend who let you test it on theirs? that's the quick way to sort if the cards bad. trying to clean up/remove the old drivers is worth a shot though
  4. Cleaned the old drivers and still no luck. Can't even get it to work for a minute now. It just freezes on power on.
  5. Board confirmed DOA. Thanks for the suggestions though.
  6. Best answer selected by bodmatt.
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