We don't do power management, this is a complicated area. Some would even say it's not to be messed with without documentation. Regardless of this it's not easy. It's the usual lack of time answer (and even with time there are few guarantees).

I currently run the proprietary driver and it runs at 55 °c, just for displaying the browser.

I'll say the main problem is the GPU itself, mine even melted a month ago, still with the proprietary driver.

With nouveau (nv50) nvclock reports my GPU is running at 85°C, was already close to  90 one day and the fans constantly run - even during "normal office work" etc.
Is that really related to "powersaving" or not? I didn't mean to save the last minute of battery-power possible but the current situation leaves me with a really hot device you wouldn't want to put on your knees while working off the desk.

It appears that this bug report has laid dormant for quite a while. Sorry we haven't gotten to it. Since we fix bugs all the time, chances are pretty good that your issue has been fixed with the latest software. Please give it a shot. (Linux kernel 3.10.7, xf86-video-nouveau 1.0.9, mesa 9.1.6, or their git versions.) If upgrading to the latest isn't an option for you, your distro's bugzilla is probably the right destination for your bug report.

In an effort to clean up our bug list, we're pre-emptively closing all bugs that haven't seen updates since 2011. If the original issue remains, please make sure to provide fresh info, see http://nouveau.freedesktop.org/wiki/Bugs/ for what we need to see, and re-open this one.

Thanks,

The Nouveau Team