Hi Folks,

so I've got this weird problem but I'd need some input/ideas to pin it down enough for a proper bug report, so I'm asking you for help.
First I need to introduce you to my admittedly non standard harware configuration which probably plays a big role in the bug since it happned on it since the beginning (so every Kernel Version from pre 3.0 to 3.3-rc3).

I've got a Tyan Dual G34 Motherboard with 2 8-Core Magny Cours Opterons
with 8*2 GB RAM one stick for each memory channel of the Opterons.
Added to that I've got a Radeon HD 5770.

On the software side I've been running Arch Linux and Windows on this system and am running 3.3-rc3 at the moment.

So here is the different situations which trigger a sudden reboot of the system:
- Running OpenCL programs with Catalyst (only ones with higher memort traffic trigger it) on Linux, it works on Windows
- Sometimes when using (with the Open Source driver) Gnome 3.x or KDE 4.x it just happens out of the blue
e.g. when maximizing a Youtube Video or even just clicking on a link, it seems to be related to the amount of change on the screen
- In earlier versions I could trigger it quite reliably by scrolling through my photo collection in F-Spot or Shotwell but the thing is only when using Gnome or KDE it works without problems in Xfce 4.8 even though I use Xfwm with compositing

The bug is triggered only in Gnome and KDE not when using Xfce 4.8 even though I use compositing in Xfwm.
So I've been running Xfce for most of the time and the system is rock stable with it not a single crash in the past few months.
It seems that some obscure GL command or something used by both KDE and Gnome makes the system unstable.

On the other hand I can play Games on Windows without problems though I've done that a lot less then using Linux so there is some chance it just didn't trigger but on the other hand the machine made it through one game night without crashes on Windows.

As the title says the bug looks like a sudden reboot and there is absolutely nothing in the logs.
The screen just freezes for 2-3 seconds and sometimes the sound stutters and then the system just reboots.

All this is much to weird and unclear for a proper bug report so I'm asking here if anyone got an idea.