6.5 -- > 6.6 CPU temperature

[jmccue]

First: T420 with latest BIOS. I also have been logging CPU temperature for a while due to a RHEL system I had at work. For giggles I log the info on my home PC also.


I noticed when I went from 6.5 to 6.6 the average CPU temperature increased by a lot. I have been reading the misc mailing list and I think only 1 person reported this issue, but is remains a mystery for him.

Since then I have been googling and experimenting with various BOIS settings to no avail. This is from my logs as of today:

6.5 ave = 49C
6.6 ave = 56C (as of now, differs +/- 3)

So I ran across cpu(4) I noticed:

Due to the way in which thermal information is reported on Intel processors, the temperature may be off by exactly +/-15 degrees C.

Interesting. What I an wondering/asking, on a Lenovo T420:

1. Has anyone noticed higher CPU temperature since going to 6.6 ?
2. is there anyway to check if I am hitting that cpu(4) condition ?
3. If not, anything to look for in order to know for real if the T420 is overheating ?

Thanks
John

[shep]

I'm assuming that you are reporting values the OS. If you reboot and enter the bios quickly, how well does the bios measured temp correlate? You should be able to get low (cold start) and higher vales after the computer has been running a while.

[jmccue]

Originally Posted by shep

I'm assuming that you are reporting values the OS. If you reboot and enter the bios quickly, how well does the bios measured temp correlate? You should be able to get low (cold start) and higher vales after the computer has been running a while.

Yes I am using

sysctl -n hw.sensors.acpitz0.temp0

hw.sensors.acpitz0.temp* reports the same, but I just noticed hw.sensors.aps0.temp0 reports 45C and it has changed since I found it. Curious what the difference is ? 45C seems more in line with what I expect.

But, are you saying your BIOS reports thermal data ? I cannot find that in my BOIS and I do not remember seeing such a thing on other laptops.

Anyway, from a cold boot the temp is very low, under 35C, but it rises to 55C - 60C on idle. For now I am hoping it is the cpu(4) issue or even hoping I am querying the wrong setting.

But any ideas will be welcome.

Thanks

EDIT: Well I did some googling and seems aps = "Thinkpad Active Protection System", which has something to do with the Hard Drive, some kind of shock resistance hardware. And it seems it has it's own thermal hardware.