In Bits

After installing Windows 7 Pro on my sister’s Dell D820, it started randomly restarting. The fans would power up to full speed for a few seconds, the screen would flash and then the whole thing would just power off, without restarting. This was obviously a heat problem, so I downloaded the great tool (which needs a better name) i8kfanGUI, which allowed me to monitor the temperatures of the CPU and the GPU. The GPU was obviously the problem, it was idling at 70°C, while the CPU seemed ok, idling at around 45°C. When I forced the fans to full power, the GPU temp didn’t come down.

Having identified the problem, I searched the internet for a bit, and found the excellent Dell Lattitude D820 Service Manual for the D820. This document is excellent, and the fact that Dell make these would make me buy a Dell in future, over other manufacturers, as this kind of information is priceless once the machine is out of warranty.

Culprit!

At this stage, I stripped down just enough to see the GPU and cooling array, which only required taking off the keyboard to have a peek. I shone a light from one side of the GPU, and could see the light shining through, there was a gap between the heatsink and the chip! The motherboard had been replaced due to faulty sound a few months ago, and clearly the engineer didn’t replace the heatsink correctly. The problem had only become apparent now, with Windows 7′s higher graphics usage.

Solved!

I went out and bought some Thermal Grease, and set about stripping down the laptop. Getting to the cooling array involves completely dismantling the computer, and I did get a fair amount of James May style satisfaction from having the entire thing laid out, screw by screw on the table in front of me. Once I got the cooling array out, the problem was even more apparent. Both of the other chips under it had (different!) grease applied, and the plate for the GPU was bare. I applied a liberal amount of grease and screwed it back up. Opening i8kfanGUI again showed the GPU idling at about 50°C, and responding to the fan – a great improvement!