My home computer recently kept powering off when doing anything requiring CPU power (say transcoding a video or editing it).   This was annoying, and I thought I’d got a hardware fault - but strangely no part of the kit was reporting errors.

So, Sunday morning after the 5th try at editing a video and a power-off (and the inevitable swearing at the computer and technology in general), I popped off the lid of the computer…

The CPU fan was “caked” in dust.     Now checking the airflow of the machine, the CPU fan sucks in air from outside (side of case), distributes it over a massive fan above the Quad core processor in the machine, which then makes the heat leave into the case.    The case then has 2 fans keeping a constant airflow front->back to expunge the air.    Basically what was happening was the airflow from outside was hitting a wall of dust at the front of the CPU fan, and thus not cooling the CPU blades and causing a thermal overload and thus a power-off by the mainboard to allow cooling to occur.    As this only occurred when CPU was over 75% utilised in normal day to day use, or when gaming it had not happened before this weekend.

A quick trip to PC world later, and air-duster in hand, the fan’s blades were cleaned (due to location, under the fan, I couldn’t get to all the blades without a air-duster).

I had not spotted this as I had not installed any ACPI monitoring to monitor CPU temperature.    Prior to cleaning the fan’s -  I went to the Asus website, installed this, and where-as pre-cleaning the CPU was hitting over 80 Celcius, it stayed at a constant 55 Celcius with the fans cleaned.

A side effect is according to my girlfriend -instead of the PC sounding like an aircraft taking off (full fan noise) - it now sounds more like a hairdryer on low…  She actually says she can work in my office now (before it was too noisy)… Although I am unsure whether this is a good thing or a bad thing !

So a lesson to all PC builders, and users - don’t forget to clean your fans on a annual, or more frequent, basis as not only will it result in a noisy machine, you may endure the pain of a thermal shutdown event by your motherboard.

Anyone else suffered this joy ?