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Two days ago, I started running into a problem with my Windows PC:

  • The PC's two connected monitors simultaneously lose signal and go black (as though the PC had been powered off).
  • The keyboard's Numlock, Capslock, and Scroll Lights will become "stuck" in their current positions, as though the PC is hung. (For example, the Numlock light on the keyboard remains lit regardless of me pressing the Numlock key repeatedly.)
  • No keyboard input does anything. (Ctrl+Alt+Del, Ctrl+Shift+Esc, Ctrl+C, etc.)
  • However -- Whatever sound/music the PC was playing continues to play, and the PC's fans continue running, so the PC hasn't powered itself off or rebooted itself.
  • Opening up the case, the graphics card is pretty hot to the touch.

I had this happen 3 times in one evening. In all cases, I was playing a game with 3D graphics when the problem occurred (Torchlight, Minecraft, Magic: The Gathering 2012, Avadon: The Black Fortress demo). I have yet to have the problem happen when I'm not playing a game.

This system has been running stable for about 2.5 years prior to this. I didn't make any changes to the system prior to the problem starting to occur.

System specs:

  • OS: Windows 7 64-bit
  • Processor: Intel Core 2 Duo E7200 Wolfdale 2.53GHz
  • Video Card: XFX GeForce 9800 GT 512 MB
  • Motherboard: Foxconn P45A-S LGA 775 Intel ATX
  • RAM: Corsair 4 GB (2x 2GB) DDR2-800 (PC2 6400)

Full specs: New PC 2008

Troubleshooting tried so far (the problem occurred again after taking each of these steps, one at a time):

  • Updated the video drivers with the latest drivers from NVidia's site.
  • Opened up the case and cleaned out the video card and processor fans (both were pretty dirty).
  • Installed and ran temperature monitor software. The processor idles at about 50 degrees C, and goes up to about 63 degrees C while playing a game (seems on the warm side, but not excessively so?). The software wasn't able to report the temperature of the GPU -- not sure this particular GPU supports software temperature readout?

My initial diagnosis is that maybe the GPU is on its last legs (given that it seems to be running pretty hot, and the problem only occurs while playing 3D games). Does this seem likely? Or is it likely that this problem is caused by the processor, RAM, or motherboard? Or could this be a software issue of some kind?

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4 Answers 4

up vote 3 down vote accepted

Could you try running the GPU-Z software and monitor the temperature of the graphics card instead of the CPU. To me this sounds quite like the graphics card is overheating and potentially failing.

If the graphics card is above 80 degrees for a significant portion of time then I would consider opening up your machine, and checking for dust around the graphics card.

In my limited experience of graphics card temperatures:

  • >70 degrees = a bit on the warm side (would prefer it lower but not a big problem)
  • >80 degrees = potential problem
  • >90 degrees = real problem
  • >100 degrees = potentially fatal problem

On the "Sensors" tab you can check the two options "Log to file" and "Continue refreshing..." So that you have (at least some) data available after the crash. When you click "Log to file" it will ask for a location to save a file, so no need to go hunting for where it stores it.

enter image description here

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Great utility, thanks for the link! It does indeed show me the temp of my GeForce 9800 GT. The utility reports that the card "idles" (Windows 7 desktop with Firefox and nothing else running) at 83 C (fan spped reported at 50%), and I saw it reach a peak temperature of 101 C (!) (fan speed 100%) after playing Torchlight for about 10 minutes. So it definitely seems a good bet that my issue is in fact related to the GPU temperature. I'll try cleaning out the card, and if that doesn't do it, it might be time to purchase a new graphics card. –  Jon Schneider Jun 29 '11 at 1:50

A software crash could do this, assume that the sound is playing in a loop (the sound buffer is just getting reread over and over).

As an aside, 60 c may seem very hot to you, but if your graphics card is that hot its not an issue (in and of itself). Try benchmarking your graphics card (try the free version of this or some other tool)

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That card should have a temp gauge on it. The software linked above will offer a log of your gpu temp and you can also try http://www.aida64.com/product/aida64-extreme-edition/overview.

I would be a little worried if my CPU was hitting 63 degrees while gaming. Have you overclocked at all? I wouldn't think a stock system would get that hot, unless something is going terribly wrong...

Any chance you can try a friend's graphics card and swap them? I had a similar problem and had to replace my card after checking each component in the system.

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The GPU overheating was indeed the problem! Removing the card from the PC, removing the card's cover, and giving the card a thorough cleaning (and then replacing the card in the PC) fixed the problem -- the card is now running at around 61 degrees C at the Windows desktop, and between 75 and 79 degrees C while playing Torchlight.

Full details: http://blog.jonschneider.com/2011/06/fix-monitor-goes-black-and-system-hangs.html

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