[adios]

I've been doing some very CPU intensive overnight 3D renderings using the Maxwell rendering app. Most of the time it works fine, but on two occasions I've sent a rendering before I've gone to sleep and woken up in the morning to find the computer's fans running extremely fast (sounds like a hairdryer) and the machine unresponsive. The computer runs fine after a restart.

Has anyone else had a similar experience, or know of any way to keep it from happening? Ambient temperatures are normal, and I have plenty of space around the computer to allow for free airflow.

I have a dual 2.5ghz running 10.4.2.

[__^^__]

I find my system gets hot with CPU intensive work but it never becomes unresponsive. Maybe it's a software problem.

[Groovy]

get temp monitor

http://www.bresink.de/osx/TemperatureMonitor.html

and log the temps of the CPU's and see if you get a thermal runaway.
the max is 68 C degrees for my Dual G5 but it may be higher (like 80 C)
for your liquid cooled G5.

Also just before a runaway it should be logged so open Console and look at your logs


If you are getting thermal runaways then first do the basic stuff like open case
and blow out all dust and check to see that All fans are working and heat
is coming out BOTH vent grilles in the back. If only one grille is hot then you
may have a bad fan, or heat sink not installed properly (may have come lose) or
your G5 needs a temp re-calibration. In that case use the G5 diagnostics DVD and
re calibrate.

You can always add more fans


if still problems then you have a bad thermal diode on one (I doubt both) CPU's or a BAD CPU
in which case you will have to take it in for repairs.


good luck

[Leonard]

Sounds like it's a simple kernel panic. The computer kernel panics and then the fans go full blast. You'd have to take a look at your logs and see why the computer kernel panics, which is often hard. Sometimes a kernel panic can be caused by bad RAM or an external peripheral.

[Groovy]

Originally Posted by Leonard

Sounds like it's a simple kernel panic. The computer kernel panics and then the fans go full blast. You'd have to take a look at your logs and see why the computer kernel panics, which is often hard. Sometimes a kernel panic can be caused by bad RAM or an external peripheral.

Well he said nothing about the KP window being on screen. "and the machine unresponsive"
is al that was said. nothing about a KP which even a new user would see the KP info on screen
and i hope mention it but yeah a KP is possible until we get more info.

I can't see how a render app could cause kernel panic directly since it should not have installed
anything low level like a kext. if the app is causing a KP and didn't install low level stuff then
my guess it is calling something in OSX that does. Example: OpenGL itself should not be
able to cause a KP but OpenGL may access something lower level like video driver function
and a bug there could be triggered.

anyway he should look in the logs because KP info is logged.

[tooki]

Well if the machine panicked after the screen was put to sleep, it would not have any way to wake the screen in order to show the panic!

It could also be a total freeze.

Either way, it means the machine is completely crashing, thus causing the fan-throttling software to stop running, leading to the fans running at full speed to prevent CPU damage.

tooki