I thought I'd just blog a little interesting thing I came across whilst fitting a new CPU to my PC yesterday. I've got an Asus motherboard and wanted to swap my Socket-A Sempron for an Athlon XP (yes, old skool I know). When I fitted the new CPU and hit the power switch, the system fired up for 3 seconds and then shut down. Thinking that maybe I'd got a fried chip - it was 2nd hand after all - I swapped the old one back in. Same thing. Started, then halted.

Worried that I'd fried the motherboard somehow, I did the whole techie thing... stripped down to a bare board and tried another PSU. Same thing. Wouldn't boot. I was about to sling the board in the bin and go buy another when I had a thought. Asus have something called CPU Overheating Protection (COP) on many of their boards, including this one. I'd been testing with the heatsink+fan connected to the motherboard but not fitted on the CPU itself. I fitted them, and hey presto it all worked fine :)

Turns out that the Asus COP somehow detects the presence of the heatsink fitted on top of the CPU. I'm not sure how - maybe pressure? Maybe some kind of induction test inside the CPU core or Motherboard? If anyone can tell me I'd appreciate it - I'm curious.

So I should really have a bit more faith in Asus motherboards, and just be impressed at the clever little things that stop me doing stupid stuff :)