apparently I am still not doing a very good job of explaining the situation... let me try again.
on 10.10 the best case idle temp is 51C on 12.04 the best case idle temp is about 57C on 13.04 the best case idle temp is 75C (that is at idle! and more typically it is low 80's) under full load: the max temp of 10.10 is 83C the max temp of 12.04 is 81C the max temp of 13.04 is 96C and climbing... (it was shutdown rather than risk meltdown) it is expected that 12.04 would be a little bit hotter than 10.10 because 10.10 is 32 bits and generic whereas the others are 64 bits and low latency. The difference between 10.10 at full load and 12.04 at full load was probably due to lack of consistency in the load itself, in any case, they are close enough not to matter. Suppose that blowing the dust out of the fan achieved an unrealistic gain of 10C in cooling. That would still leave 13.04 at 86C (or higher) which really is still too hot. However, blowing the dust out of the fan would be expected to affect all of the oses equally. So that still leaves us with a differential of 75 - 51 = 24C at idle and 96 - 83 = 13C at 100% load, between the oses. That is a huge difference and the only source of that difference is the software. If I were running these tests years apart, that would be a different thing, and it would be reasonable to blame dust for the difference, but I am not; instead I have a multi-boot setup and I am running the tests within ten minutes of each other, so hardware differences are ruled out because it is the same hardware and the same amount of dust. Furthermore, on 10.10 when the temp gets down to around 55C, the Fan Shuts Off... therefore however much dust there might be, it is not even a factor for the temperature of 10.10 because under light load or idle it does not even use the fan. With the other os versions the fan never shuts off, but 12.04 can get pretty quiet, 13.04 the fan is always loud even at idle. so there is indeed a very serious problem here. I started out thinking this was a video driver issue, because I started out with the observation that at idle up to moderate loads the video was consistently 2 to 3 degrees hotter than the other temps. However, in further testing I observed that at high loads the other temperatures greatly exceeded the video temperature. So at that point I back-tracked on my assumptions about the video driver being the sole culprit. It has been my experience as a programmer that when one is presented with a complex set of symptoms, it is usually the result of multiple bugs appearing to be a single problem. So, I'm inclined to suspect that there is a problem with the radeon but that there is also a problem with the cpu scheduler too. Right now I am working on two things. The first thing is that I have done a fresh clean/new install of 12.04, because my main version of 12.04 has had a lot of changes made, so I want a pristine os for testing. The other chief advantage is that on the stock os, lm-sensors is able to read the radeon temperature, but on my main 12.04 lm-sensors is no longer able to read the radeon temp. So, with lm-sensors working properly we can have a direct comparison with 13.04. The second thing that I am working on is trying to solve the problem of why lm-sensors can't read the fan speed. I think it would be very helpful to see exactly what the fans are doing. Now, in preliminary testing of the 12.04 new install with nothing added (except temperature reading software) and no updates I was very surprised to see that it was running substantially hotter than my main 12.04 which has had zillions of updates and other changes. This is a preliminary finding I ran out of time and was not yet able to pursue this further, but the result was quite surprising. Something else that I have played with a little bit is the scheduler mode. Changing it from OnDemand to PowerSave shows cpu use going way up at the same time that temperature goes down. The problem appears to be that the time spent on power saving is not being properly accounted for in the cpu load calculation. HTOP returns numbers that are nearly identical to my own program's calculations, so it may be a problem with the kernel's accounting. Bottom line is that there is an overheating problem, in fact it may be two different problems, and this is a serious issue because it can lead to hardware destruction. But figuring out what the problem is, is going to be difficult. I am working on some more tests to try to make the situation clearer. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1166916 Title: temperature overheating of cpu and radeon in 12.10 and above To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1166916/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
