AMD Athlon 64x2 TK-55
Radeon X1200
Ubuntu & Xubuntu 9.04
Kernel 2.6.28-11-generic x86_64
First of all, this looks like bug #22336 from 2005-2006, It has happened 6 times while doing different things.
After several hours of npviewer being active in firefox (3.0.10+nobinonly-0ubuntu0.9.04.1) the laptop suddenly shut off without warning.
Gimp (2.6.6-0ubuntu1) while doing different CPU demanding tasks (selection from path in a large image, script-fu and others) same problem (shut down without warning) appeared.
I've been having other problems with the video driver (radeonhd) since I upgraded to jaunty, but this seems like an overheating problem.
I've been monitoring CPU's temperature via lm-sensors and it doesn't go below 64° C., critical temperature is 102° C.
CPU frecuency scaling "on demand" runs processor at 44% but simple task like launching the gimp rises temperature 8° C and CPU frecuency to 100%.
Thanks.
Diego Liedo.
I solved the problem, I'm sorry about having it reported as a bug, I just got desperate.
It was a dirty fan issue, however, does anybody know what's the normal operation temperature of an athlon 64x2?
Mine goes from 55° C to 71° C now that is clean.
Ignore this bug report, it wasn't a bug.