So I got home from work yesterday and went to turn my computer on as per usual to be greeted by this:

The screens remained black, so I rebooted; I go as far as GRUB before my screens went black again. I rebooted again, they didn't turn on. I rebooted again, I got as far as the windows login screen.

This time I unplugged it, opened it up and cleaned it but to no luck. The GPU was still being tempermental. I repeated the process of turning off and on several times until one time it work as normal. I happily played games for the rest of the night (5-6 hours?) thinking everything was jolly good now.

Well I get home from work today and it is doing the SAME thing. Sometimes everything displays normally for a few seconds to minutes then the screens go black; then sometimes the screens don't come on at all.

Summary and additional points

  • Screens sometimes turn on before shortly turning off, sometimes they don't; I cannot seem to determine any pattern between when they do or do not turn off.
  • The build has been working fine for about 8 months now so I know it's not hardware incompatibility.
  • If I plug a monitor into the on board graphics I can use the PC normally (just in low graphics mode)
  • I have two monitors and it's a case of they both turn on or not. So I think I can rule out the monitors being dead.
  • I have tried replacing the GPU
  • I have tried replacing the RAM
  • I have tried flashing the CMOS
  • I have tried cleaning the inside
  • The GPU is a Radeon HD 7870

My questions

Is my GPU dead?It's not very old and I would rather have a method of being certain it's the GPU before I fork out some money I can't really afford.

I do not have a second PC here to test it in.

If my GPU is dead why does it sometimes work and sometimes not?


Update

Okay, it was working again.. at least I thought it was. I left it running for 10-20minutes with the screens black. Turned it off and straight back on and it worked for all of 10minutes. I was then updating the post in joy thinking I could play some games for the rest of the night when BAM it went black again. So yeah, I don't know :C

  • RMA the card. ...– ShikiNov 10 '13 at 21:14

Running for a while and then shutting down sounds a lot like overheating.

Based on what you say you've tried, that seems to only leave the power supply or the mother board.

You say you replaced the GPU. I'm assuming the other GPU also failed. That would rule out your GPU as being at fault.

Perhaps the power supply is not adequate for that model GPU? Or perhaps the power supply is failing?

It could also be a cracked mother board. I had one of these. The machine would run fine for a while and then get flaky. Finally, after moving the machine, it wouldn't come on at all. Fans would turn but no beeps and no video. I replaced the motherboard and now all is well.

    Might be a bad power supply. Try swapping it out for a new, and try to get a higher wattage one while you are at it.

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