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Date:      Mon, 05 Aug 2013 01:30:03 +0100
From:      Frank Leonhardt <frank2@fjl.co.uk>
To:        freebsd-questions@freebsd.org
Subject:   Re: AMD Phenom II X4 temperature issues  (was Re: hardware monitor)
Message-ID:  <51FEF20B.2090503@fjl.co.uk>
In-Reply-To: <51FEE3E0.5080709@blackfoot.net>
References:  <51FEBE38.2000202@blackfoot.net> <20130804231548.dbb1fd2e.freebsd@edvax.de> <51FEE23D.3020402@blackfoot.net> <51FEE3E0.5080709@blackfoot.net>

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On 05/08/2013 00:29, Gary Aitken wrote:
> On 08/04/13 17:22, Gary Aitken wrote:
>> Ok, so now I see that my cpu temperature shoots up pretty dang fast when a
>> build is going on.
>>
>> I'm running an AMD Phenom II X4 with the AMD-supplied fan in an
>> ASUS M4A89TD PRO / USB3 motherboard.
>>
>> The system "works fine" unless I start a cpu-intensive build.
>> If I leave it unattended, after some time the system shuts down abruptly.
>> I'm guessing it's because of excessive cpu temperatures.
>>
>> When doing port builds, or any cpu-intensive job, the temperature of the
>> CPU goes from 45 to 50 in about 30 seconds.
>>   
>> I pretty much have to manually suspend and resume the build process
>> to keep it down.  If I do that, I avoid the abrupt shutdown.
>>
>> Needless to say, this makes unattended operation a non-starter...
>>
>> Does anyone else have a similar setup they can provide me some related
>> experience on?
> BTW, the mobo temp stays down around 32.
>

Did you get that from the ACPI?

Obvious answers are a bigger fan, but a lot of home-build machines don't 
match the airflow through the case properly - if the CPU fan is blowing 
pre-warmed air on to the CPU it's not as good as blowing outside air.

50C isn't crazy. Some would say that was barely warm, in fact. Cooler is 
always better, but you possibly don't need to worry about this. Some 
CPUs use what they call passive temperature management, and power 
management, which means they increase or reduce the clock rate depending 
on the workload and whether it's getting too hot. Faster switching means 
more heat. So getting hotter when doing a lot of work makes sense and 
could be expected. (Winchesters really heat up like you wouldn't believe 
when you move the heads a lot).

Did you get anywhere with the ACPI suggestion (you emailed me privately, 
whether you meant to or not, but didn't mention the outcome). There's a 
lot there in the ACPI you might want to look in to, including fan 
control. If I understand it correctly, "passive cooling" will be engaged 
by acpi_thermal if the cpufreq drivers are in use, which may not be what 
you want. Try hw.acpi.thermal.tz0.active=1 to make the fan come on and 
stay on (tz0 or as appropriate).

Here's the fun part. Is your system doing a thermal overload shutdown? 
it will say so on the console, or in the message log. You didn't say, 
you just said it "shut down". If it's deciding to shut down through 
over-temperature it does not necesarily mean it's overheating; it could 
be that it has incorrectly set the shutdown temperatue for your CPU to 
be far too low - possibly because it doesn't recognise it and is being 
over-cautious.

it might help if you posted the results of "sysctl hw.acpi.thermal", but 
in the mean time look at:

hw.acpi.thermal.tz0._HOT
hw.acpi.thermal.tz0._CRT

(replace tz0 with whatever tz you're worried about).

The first is the temperature when the system is supposed to stop what 
it's doing and suspend to disk (if it can). When it reaches the value on 
_CRT it'll write a message to the log file and shut down immediately to 
prevent damage. You can set these to whatever you want, but you have to 
set hw.acpi.thermal.user_override to 1 first before it will let you. 
Final trick - make sure you specify the temperatures like

sysctl hw.acpi.thermal.tz0._CRT=80C

Don't specify it as 80.0C (as it will display) and don't forget the C or 
it will assume degrees Kelvin!

Regards, Frank.







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