My Dell overheating mystery solved

Ok, so I’ve just bought a nice new Dell Quad Core machine. It’s fast, it looks good, and it’s dead quiet. Or at least it’s quiet until you ask it to do anything.

For the first week of ownership I put up with ridiculously loud fan speeds when the machine was under load. I’m not just talking the occasional whir, I’m talking tornado force speeds off the CPU fan. It was loud enough that I had to shout to other people in the room, and fast enough that the cables were visibly blowing around inside the case — this s*it was crazy!


So I decided to call Dell today and get help. The call started out well enough, going through a list of automated options with some cheery Irish computer voice. Then I got transferred to an operator in India. I explained the problem as clearly as I could: “When the machine is idle, the CPU runs at about 45C. When it’s under load those temperatures rise to 100C and the CPU fan goes to full speed. Even at this high temperature, the heatsink remains completely cold to the touch. I think the heatsink needs reseated. Could you talk me through that please.”

Cue a full hour of pointless software debugging and debate with the technician. During the call he asked me to start a remote desktop session for him, go through lots of Task Manager settings, restart the machine several times, etc, etc and in the end conclued that there is no problem.

  • Dell: “You have bought a server machine Sir, these machines are designed to run hot, your power supply fan may become hot”.
  • Me: “It’s not the power supply, it’s the CPU that’s hot. And I don’t believe 100C is within spec.”
  • Dell: “Yes, your CPU is designed to run at 100% temperature, do not worry.”
  • Me: “The temperature isn’t 100%, it’s 100 degrees centigrade. Isn’t that hot? Do you know what the maximum temperature is supposed to be.”
  • Dell: “Yes, it’s supposed to be 100%.”

After another round of this debate, I asked to speak to the manager. His answer was just as random: “Sir, you should allow your machine to run for at least another couple of weeks. After this time the temperatures will start to come down.”

Finally, I convinced him that some action was required now. He demanded that we start with a full re-install of Vista because my machine was running “too many processes”. I explained: “This is not a software issue, it’s a hardware problem. Please let me speak to a hardware technician.” After another 10 minutes of waffle I gave him an ultimatum: “Either let me speak to a hardware technician or end this call.”

plastic.jpgFive mins later I got a call back from a hardware tech. He didn’t seem to have a clue about my machine configuration, giving me instructions for removing the heatsink from a non-Quad machine. Once he finally got the right instructions in front of him, removal of the heatsink was relatively painless. At this point the cause became quite clear… there was a plastic insulator trapped in the thermal grease between the CPU and cooler.

I told the tech what I had found. He said: “Yes, this plastic is ok, all Dell plastics are engineered to the highest specifications and are completely safe. Please do not remove it.” I tried again to explain that this really shouldn’t be there, but he stuck to the party line. I removed it anyway, reinstalled the heatsink, and the machine is now very quiet and relatively cool — 32C at idle and a max of 75C under full load. I suspect replacing the thermal grease would reduce temperatures further, it had been applied quite badly.

Here’s the setup, quiet and cool…