Fix: Monitor goes black and system hangs while gaming (video card overheat)

Earlier this week, I started having an unpleasant problem with my PC: While playing a game, both monitors connected to my PC would go black (as though the PC had powered off), and the system became unresponsive (the Num Lock light would no longer turn on and off when hitting the Num Lock key).  However, the music the game was playing would keep playing -- indicating that the PC hadn’t totally hung or shut down.  Opening the PC case, I noticed that my video card was very hot to the touch.

I had this happen three times in one night, in all cases happening while I was playing a game.  (It happened originally while playing Torchlight, and then again later while playing Magic: The Gathering 2012, and once again while playing the Avadon: Black Fortress demo.)

Given these symptoms, my original suspicion was an overheating-related issue with my video card (GPU), a XFX NVIDIA GeForce 9800 GT.  (The problem seemed to happen while the video card was under load; the system caused the monitors to go black but sounds kept playing; the video card was hot to the touch; the problem happened intermittently, across multiple applications.)

I posted the problem to SuperUser.com and got a helpful reply from user “Mokubai” confirming that the problem was indeed likely due to a GPU overheat, as well as a link to a very helpful free utility, GPU-Z, which (among other features) provides real-time reporting of the current GPU temperature.

I downloaded and ran GPU-Z.  It reported that the video card temperature with my PC just sitting idle at the Windows desktop was 83 degrees C (hot!).  I put GPU-Z on my secondary monitor and fired up Torchlight (a 3D game) in the primary window; after playing for just a few minutes, GPU-Z reported that my video card was up to a maximum temperature of 101 degrees C (extremely hot!), with the card’s fan running at 100% speed.  Clearly the GPU temperature was almost certainly to blame for the problem of my monitors losing signal and the PC hanging.

Tonight, I had some time to work on the problem, so I shut down and unplugged the PC and then removed the video card. The card was pretty grimy with dust.

I used a small Phillips screwdriver to remove the six screws holding the “cover” onto the card, and then removed the cover itself. Having done that, I could see that there was a lot of dirty material stuck in the narrow grooves of the heatsink, which was likely obstructing the air flow through the heatsink and preventing the card’s fan from cooling off the heatsink, causing the high temperatures.

I took a pipe cleaner and cleaned all of the gunk out of the heatsink, the fan blades, and the other parts of the card. Much better!

(Images above: Left, XFX GeForce 9800 GT with cover removed, before cleaning; Right, after cleaning.)

Having thoroughly cleaned the video card, I replaced the cover and the screws, reinstalled the card in my PC, and then powered the PC back on.

The result: Much improved temperature readings from GPU-Z!  The GPU now idles at the Windows desktop at 61 degrees C, and hit a maximum temperature of 79 degrees C with an average temperature of around 75 degrees C while playing a session of Torchlight.  The video card’s fan speed never went above 43% while playing the game, indicating that the card itself didn’t think that it was running too hot.

Given that I was originally considering buying a new video card to deal with this problem – a solution that would have run me in the neighborhood of $100 – I’m pretty happy that I was able to fix this issue of the monitors going black while gaming “for free” just by taking a few minutes to give the video card a good cleaning.