GPU overheats with nouveau (ok with nvidia proprietary)

[lcampagn]

I am using kubuntu 12.04 on an HP mini 311, desktop effects disabled.
Originally I was using the nouveau driver. For the first couple of weeks I used the machine, it would suddenly and immediately shut down a few times a day, presumably due to overheating. I put the CPU through some heavy load tests which did not result in any problems, but noticed that I most frequently experienced shutdowns when viewing video.
I have been monitoring one of the internal temperature sensors "acpi/Thermal_zone/0/Temperature" which was usually around 90C. Since switching to the nvidia proprietary driver (~2 weeks ago), I have had no problems and the temperature is around 65C most of the time.

All of this leads me to believe that the nouveau driver was causing the GPU to overheat, but this is still somewhat speculative so I'd be happy to run some tests if needed.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic-pae 3.2.14
Uname: Linux 3.2.0-23-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu5
Architecture: i386
Date: Wed Aug 15 23:39:15 2012
EcryptfsInUse: Yes
InstallationMedia: Kubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
ProcEnviron:
 LANGUAGE=
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xserver-xorg-video-nouveau
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.