After testing all night (I tweaked the registry settings for the power threshold and so on), I finally found the problem.
The conclusion is very simple ;-)
For some reason world of warcraft sync at 50 fps instead of 60 fps,
but still shows a frame rate in the stats (or with fraps) at 60 fps.
This gives the very choppy situation.
I could see it because after doing an exit of wow, the config.wtf was updated with those lines:
SET gxVSync "1"
SET gxRefresh "50/1"
When you restart the game, the line SET gxRefresh "50/1"
is then automatically removed (funny, they add them themselfs but then remove it).
I took a picture where it was for some reason indicating that the frame rate setting was not matching the preferences (and so the light came in my llittle brain after all ;-).
So the easiest solution to solve it is to select 50 Hz in the settings (when in full screen mode), apply it, then 60 Hz and apply.
Blazing smooth game now, with beta file name AMD_Catalyst_14.3_Beta_V1.0_Windows_B22_March12.exe
If you play in windows mode, play with the catalyst screen refresh rate of bit depth, that also works making wow aligned with the GPU.
I hope that will solve at your side the stuttering.
Let me know if that is the case ;-)