Originally Posted by Darkmgl

I can't say I have the same extreme conditions as you do but FPS has been in a steady decline. If you want some comparison numbers, in Windowed Mode 1680X1050 the lowest I ever drop is 35-40, never under 55 fullscreen and thats usually Illidan/Hyjal on a E6600 with an 8800gtx.

The game generally bottlenecks at the CPU or Memory assuming that you have at least an Nvidia 6800GT/7600GT card or better/equivalent. People have been trying to pin down your bug for a long long time. It seems to happen on systems with no rhyme or reason.

The only things I've noticed that people tend to overlook are forgetting to disable CPU options like C1E or EIST/Intel Speedstep. Other then that, I have no idea. The issues seem to only occur in WoW and not other games which means it has to do with how WoW handles something.

Things I would try: Loosening Ram Timings, Non ECC memory, dropping to 2GB, reinstalling the operating system, double checking C1E/EIST and making sure they are disabled. Disabling sound/lowering acceleration. You can double check overheating, I doubt it is that. I've only had 1 in 17 recent cases of WoW issues caused by actual overheating. You can double check your video card settings and make sure AA/AF are set to application but you don't seem like the sort of person who is stumbling around without knowing stuff like that.

I wouldn't expect anything to help, but knowing where WoW bottlenecks I would be looking at that. If its not those, it is most likely beyond your control and Blizzard is screwing up something in the Dynamic Link Libraries or some sort of unexpected interference from an obscure piece of software.

For some freakish reason, my WoW stutters if I don't start Windows Messenger 4.7 on my computer first. I can quit messenger after it starts, yet if I don't run it at least once I stutter every time I use a skill. The only thing I can imagine is something relating to dual core processors or how WoW is handling a certain .dll being screwed up until Messenger happens to fix that specific instance.

Particle effects seem to be the big FPS hitter. It wouldn't surprise me if something was messed up in their Pixel Shader code too.

I hope you find what you are looking for, I feel really bad for everyone who has these problems because Blizzard has managed to screw up some bit of code and will not admit to it.