You've either got some bad JPEG compression, or the game has some real weird and serious noisy banding issues.
Thats super rad.
Have you got a modlist for Witcher 2? I'm playing through it as soon as I get the mod situation figured out for my first playthrough and your set up looks real good.
Only 2 mods :
The recently released Enhancement pack which includes lots of stuff and the vivid eyes mod .
optionally you might also look into the Medallion Cooldown Reduced mod if you get annoyed by having to wait 10 secs between uses .