stress-testing the new Nexuiz release on my rig makes my system with a HD 3850 have nice X freezes (or black screens) on Ubuntu 8.04 x86-64.
Booting into windows I noticed I can easily push the gfx card to 92°C without the gfx card fan speeding up audibly (and without crashing). On Linux I once got it to sound a bit like a vacuum cleaner, so I guess the card may get even hotter with fglrx.
Dumb question: Is there a tool for Linux to read the gfx card temperature? It may be the temperature, it may be some unrelated fglrx-specific thing, but without sensors I just can't tell. I find it rather disappointing that the catalyst control center doesn't offer thermal monitoring (the last card without sensors I had was a Nvidia FX5200...) - but then again there may be bigger issues.
It _could be_ a couple of years before temp reporting is included, but new driver releases have been pretty regularly forthcoming at roughly one a month. Most cases you could print the changelog on a matchbook, but they've been releasing new versions as promised.
I've disassembled parts of aticonfig a while back and found some hidden options.
Some of them were temperature related. Most things didn't work here but my card is pretty old. It's also possible that some things have changed in the meantime