Annoying Amnesia The Dark Descent graphics glitch

[Thomas]

This must be a driver bug of some sort and the problem is that occlusion queries does not seem to work. This is very serious as it is a central part of the engine.

Have you tried turning off Windows Aeon in case you have that?

Also, when updating drivers, did you download them from the ATI site?

Could you please also try the compatibility test here:
http://frictionalgames.com/forum/thread-3656.html

And post a link to the post you made. This will be very helpful for any debugging.