MaximeMartyr: I have the "hair twitching like crazy" issue, but I have only one GPU so this is not caused by SLI or Crossfire...
Since you took part in that topic as well, why didn't you update this fixes to common problems topic to say:
"Enable V-Sync in your GPU control panel"
I'd just like to add, enabling V-Sync in the Nvidia control panel does stop the hair and beard twitching in Chapters 1 & 4, but causes Triss' hair to glitch in the starting scene of Chapter 3.
So I enable v-sync when beginning the game, and disable v-sync once I'm in the mages tower, before going out to face Javed.
Then re-enable it in Chapter 4 before speaking to Abigail.