Comment 271 for bug 22336

hi everyone

i just ran into this overheating+shutdown issue with an amilo a1650 laptop, mobile sempron 3100+ (800, 1600,1800 MHz steps), gentoo 2.6.24 and 2.6.28-r10. in my case this was clearly a problem related to horrific thermal paste situation. afaik nobody has touched the cpu+hsf since the machine came from factory some years ago, but the cpu idle temperature was 56 C @ 800MHz. using performance or ondemand governor the cpu temperature would almost immediately skyrocket to 100+ C and the machine would almost immediately power off.

before, this laptop had run windows xp for a almost 2 years now where it also exhibited some occasional freezes and shutdowns, although it would not do it so abruptly, and freezes also seemed to be related to which Mobility Radeon 200M IXP video driver i would use (the newer, the worse!). but overall it would be in a working condition, although you could visibly see (ProcExp) it would throttle to 800 MHz way too often and bog down any task which hogged the cpu for any period of time.

yesterday i opened heatsink up and saw the thermal paste was in a terrible situation, as in it looked like nothing you would expect from a decent thermal paste application - hardened into pieces, scattered around the core, with random blobs stuck on the heatsink. applied some arctic cooling mx-1 and voila - it looks to have a worked. cpu idle temperature was 36 C after booting up, stabilizing at around 45 C @ 800 MHz after staying on for a while. i'm using ondemand governor, so 800 MHz is the usual working speed. in performance situations, the temperature does ratchet up double and more, but thanks to decent thermal paste, the fan has more time to kick in at higher speed and now the maximum temperature during 'make bzImage' was 98 C for a second. the cpu does get automatically throttled down to 800 MHz at high temperatures with performance governor, then switched up again at around 65-70C.

i also and monitored and graphed it (attached).

as you can see, these crappy low end laptops are just not very good performance or gaming machines. the cpu burns up easily and hardware has to scale back the MHz, killing any chance at high performance for extended periods. fortunately this one will do nothing sit idle most of the time with office work, so 800 MHz with occasional bump-up should work fine from now on. but obviously it's a worrying sign that coming out the factory, it was ill-prepared to do even that. googling "amilo overheat" is a clear indicator of that.