You truly are a magicien -> it worked exactly as you say so !
I rotated my desktop back (90 degrees) and Hyperspin is displayed correctly, no clatter, no sound distortion, perfect resolution !
EDIT: Oh, and disabling Aero was indeed the right thing to do to fix the jerky videos
However , i tried several games just to check, and oddly, i found one game that still gives me the clatter
Here is the log, hopefully you'll figure out why ?
Alas, as for me, like yesterday night, i have to go to sleep because i'm working early.
One more time, thanks a lot for your help, and see you tomorrow !