do anyone have any confirmation regarding the problem that matrices says is misunderstood? Do people who have vsync off suffer an other problem that are similar to the one you describe with vsync on?
Or what's going on?
Well I never really had problems with tearing in 3x1 landscape w/ 6950 w/ vsync on or off. A few games that are bad about tearing like civ 5 would do a bit of micro tearing when you jumped around the world.
In 3x1 portrait mode the DVI/DP timings is correct. Portrait is imo virtually unplayable on a 6950, 5 minutes will give you a nasty headache as one screen will have constant lines which mess up your peripheral vision.
I ended up getting a full refund and upgrading to a Asus 6970 DCU2. Three DP cables going to 3 DP native monitors. Everything works well in portrait or landscape, V-sync definitely reduces some tearing in some games in portrait mode.