High temperature on FreeBSD

Peter Maloney peter.maloney at brockmann-consult.de
Tue Mar 13 13:59:44 UTC 2012

Am 12.03.2012 03:29, schrieb alina at sc.rimed.cu:
>> You have a cooling or hardware problem. The problem isn't FreeBSD.
> Thanks you everybody but if it's a hardware problem then why i didn't have
> it in Fedora; the problem did not appear at this time, i install the
> system and !bum! the first shutdown for thermal reasons (was only coping
> my backup).
Maybe the OS affects the fan speed somehow, but you still can't say it
is FreeBSD, since you haven't tested it enough. Maybe your Fedora usage
just never heated it up. Maybe your fan quit recently, after the last
time you heated it up. Maybe it is because winter has ended, etc.. Also
check the bios for fan settings, and consider turning off automatic fan
speed control if low noise isn't too important for you.

Definitely clean the fan and heat sink. I think compressed air in a can
is the way the pros do it. A vaccum cleaner on reverse does a good job.
If it doesn't have reverse, it takes more skill or much more power to
get all the dirt without taking it apart. Don't take the heat sink off
and put it back on... it will kill your cooling. If you did, see next
paragraph. Also, clean out any dirt anywhere else, such as the power
supply fan, video card, etc. while you are at it.

If you removed the heat sink any time during the life of the machine,
you destroyed the thermal goo. To put the heat sink back on, you need
new goo. This means scubbing off the old goo using rubbing alcohol,
making sure the surface is smooth, then reapplying fresh goo (buy
expensive goo... it costs double [$0.20 instead of $0.10... pennies] but
it is worth it). Then when putting the heat sink on, make sure it is
firmly and evenly attached. If not, figure out what went wrong (happened
to me once with a 3rd party heat sink, and I had to file something down
and put the cpu in slightly crooked for it to press evenly). If it dries
up before you are done, then clean again and repeat with new goo. (it
probably takes a day to dry though). Using old goo means it is not goo,
but solid, and after you pulled and stretched it, it, it has bubbles and
cracks in it.

Then do a good test. eg. listen to the fan to estimate if it runs faster
in FreeBSD or Fedora (obviously this would be a rough measurement, but
sometimes there are 3-4 settings that you can hear differently). Make it
run hot (compile something on both OSses), and feel it with your hand.
Don't trust software that reads sensors unless you tested it (numbers
might not be comparable with different software, and sometimes it is
just plain wrong. eg. I have a server that says it is -40°C). If you
have a thermometer, use that. Make sure to give it time to heat up.

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