Laptop overheating with F 16

Adam Williamson awilliam at
Mon Sep 12 21:57:42 UTC 2011

On Mon, 2011-09-12 at 13:39 -0800, Erinn Looney-Triggs wrote:
> On 09/12/2011 11:45 AM, Adam Williamson wrote:
> >
> > If you don't do anything in Windows to cause extended high CPU usage,
> > then obviously the system temperature will remain lower.
> >
> > I suspect if you, say, ran Prime95 for a while in Windows, it might
> > reproduce the issue.
> I ran stress -c 5 (I have 4 cores with HT) on the laptop and was able to
> generate the CPU thermal events under F 16.
> So I then ran prime95 in windows for about an hour, didn't get anything
> in the logs, though I don't pretend to understand windows logging
> structure or to even say mine is set up correctly.
> So I then switched to booting F 15 from a rescue disk, and chrooting
> into my F 16 install and running stress -c 5 again (basically a long way
> around to booting an older kernel), and I was unable to generate the CPU
> thermal events.
> I doubt this is an apples to apples comparison, but it is about as close
> as I can get with what I know. Is it possible the F 16 is just logging
> more information and that is why I am seeing this error? Like I said
> never saw this with F 15, you believe it is HW, I don't buy it yet, so
> is there something else that could explain it?

yeah, that does point to something else, which is interesting: it's hard
to see offhand how F16 could be running a lot hotter than F15 or Windows
assuming you ran up a heavy load on all of them. I suppose the graphics
card could be running hotter in F16 for some reason and that'd be
pushing it over the edge.

AIUI, the actual overheat cutoff levels and the overheat shutdown
mechanism itself are implemented in the system firmware (BIOS) and Linux
just passes along the messages, so it's not that these overheat levels
are different in F16, or exist in F16 but don't exist in F15 or Windows,
or anything like that. I'm pretty sure it must actually be the case that
your system really is running physically hotter in F16.
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | adamwfedora

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