On Montag 26 Oktober 2009, Grant wrote: > >> After upgrading from 2.6.28 to 2.6.31, I noticed my CPU temperatures > >> are reported a full 20C hotter. If I load the old kernel, the > >> reported temperatures drops back down to normal. Has anyone else seen > >> this? > > > > If you're using coretemp as sensor, the temps are always off (the > > coretemp sensor of Intel chips is not accurate, not by any stretch of the > > imagination.) It only reports the distance to the CPU's maximum thermal > > junction, which then the coretemp driver *tries* to translate into a > > temperature, but the result is wrong since the value reported by the CPU > > is not accurate to start with (it only gets accurate as you approach the > > max value). That maximum value is totally undocumented for desktop CPUs > > (the docs Intel provided recently are wrong.) > > > > You should use your mainboard's sensors instead for accurate values. > > I'm actually using k8temp. Do you think it is susceptible to the same > problems you're talking about? I also have an ACPI sensor available > named THRM. Should that one be more accurate? > > BTW, another system of mine (Dell laptop) only seems to have available > coretemp or an ACPI sensor which reports values like 46960 mWh. Am I > totally out of luck with that one? > > So, In the end, it's fairly impossible to monitor a CPU's actual > temperature in order to keep it below the published maximum? > > - Grant >
there are no published maximums. Ruin a good evening going through CPU specs. And k8temp has the same problem. Or similar. Some CPUs report correct temps, other doesn't and some report some complete bogonium.
