I played yesterday again and the problem with the huge pixels didn't appear anymore, guess that was just happening because I was playing around with the settings. Because that was when it actually started.
Played Stalker with Nvidia and shutterglasses before, too. But I have to say that the monitor with it's own drivers is a huge step up from that.
3D wise everything in the game is just perfectly fine, it's only the UI that is messed up.
Actually I hadn't even checked the post processing but that should still be disabled from when I played with Shutterglasses. I will check this weekend, perhaps that was the problem.
Crosshair works fine in 3D and when I walked by 2 crosses from graves, with one having the gas mask still hanging over it, on top of a hill yesterday that was just an amazing scene in 3D
Great game for 3D, it's just the UI I have to check out to get working properly.
Wouldn't switch back to shutterglasses though