That's an interesting Warning, @UglySpirit. I couldn't find much about it googling except this: http://winhlp.com/node/43 This article states:
"As I found out much later, the errors are triggered by programs like temperature monitors or DVD playing programs, which query the ACPIEC chip for temperature or battery charge information or similar. The DVD player WinDVD, for example, does it to find out whether the battery of a laptop is running low."
1) What CPU and GPU temperatures are you logging when your TDR error occurs?
2) Bad RAM and bad Power Supply are also possible causes of TDR's. Have you run memtest86? Does your TDR occur while on A/C with battery removed? Does it occur on battery?
3) Does the TDR occur outside of Dawn of War 2 (i.e. can you reproduce it with a stress test)? If not, it could be game-specific, where the developers of Dawn of War 2 need to issue a patch. Have you lurked/posted on the Dawn of War 2 forums?
4) What does DPC Latency Checker show you?
5) Have you tried a clean Windows 7 install and still get TDR's?
As I replied to @jabba77, the thread http://forums.nvidia.com/index.php?showtopic=215256 indicates NVIDIA is seeking Memory Dumps and other information from customers who experience TDR's with their version 285.xx and later drivers. I would go to the NVIDIA forum and research there for awhile before doing an RMA - maybe even get directly involved with NVIDIA tech support.
With the info you have provided to date, I think there's a better than 99.9999999999999% chance it'll be returned to you from RMA with the same issue.
EDIT: I see you also reported video corruption in Crysis 2 in your other thread. I'd be tempted to perform a clean Windows 7 install with the NVIDIA WHQL video driver for your system. Then attempt to reproduce the video corruption you reported in Crysis 2 with a stress test (to eliminate possibility of it being a game-specific error) and see if it also occurs in an external monitor.