Comment 114 for bug 22336

I think some people are barking up the wrong tree with this one. There is a problem with the CPU overheating, but it has little or nothing to do with throttling, as the complaints are about the CPU overheating when CPU usage is *supposed* to be high (ie compiling applications, etc)

Throttling is a technique meant to be used during periods of *low* CPU usage. The purpose is to reduce the power consumption of the CPU when it isn't doing much. You're not supposed to throttle the CPU when it's doing a lot of work except in a dire emergency, because that defeats the purpose of having a fast CPU in the first place. A CPU that's throttled whenever it's doing a lot of work is essentially one that may feel slightly more responsive than an equivalent machine with a CPU that runs at the slower speed by default, but is otherwise just as poorly performing.

I have a Thinkpad T60. Until a couple of weeks ago, I was running Debian sarge with a 2.6.16 kernel. I can tell you what's different between it and the Feisty install I have today: on the Debian machine, when the fans needed to come on full blast, they did. On the Feisty install, they don't. Even typing "# echo level 7 > /proc/acpi/ibm/fan" to force the fans to their highest "supported" speed is not enough to actually get them to go at their documented rate. They certainly aren't making the same amount of noise. The only way I can permanently prevent my laptop from overheating is to override the rate control altogether with "# echo level disengaged > /proc/acpi/ibm/fan" which does get the fans up to full speed, but makes it permanent (whereas under Debian, the fans would only go to full speed if the laptop really was doing a lot of work. The various OpenGL screensavers and Unreal Tournament would do that.)

If "level 7" fans meant the same thing under Feisty as it did under Sarge, I don't think there'd be a problem.

I can manually enable throttling and have done so, but the result has been somewhat unusable: whenever I start anything from installing packages (gzip uses CPU...) to compiling a large program, the CPU speed plummets to something barely usable. I'm failing to see the point. I can see using it if the CPU approaches an unsafe temperature even when fans are on full blast (essentially as a last resort, to save the system from either burning up or turning off), but not if simply bumping up the fan speed would do the job.