Can't Vsync with 4k Crossfire

[vikeyev]

Specs
Asus PB287Q

Noticed it first with Skyrim and then with Black Mesa (also tested in CSGO, HL2, MK Komplete, Guild Wars 2 and others). At 4k I get either very chronic screen tearing,  very bad micro stutter or flashing shadows in some games (the shadows are usually fixed by changing the crossfire settings in CCC or turning shadows down). If Vsync happens to work in a game it fixes the micro stutter and screen tearing...sadly it rarely does.

Whether I activate it in CCC or in game it caps my framerate at 120fps and as a result doesn't solve my problems. If I drop the Res to 2k, it works, if I disable 1 GPU, it works (with a massive hit to performance on games that I really need it in). I've tried all sorts of settings and I just can't get it to work for me.

But I have noticed 3 unusual cases.

The first, Metro Last Light, Vsync works fine on 4k Crossfire (graphics settings turned down so I could reach 60fps lol).
The Second and Third, Payday 2 and Crisis 2. Vsync caps framerate at 30fps, so I checked my monitor settings to make sure it was still at DP1.2 (Google Images pic, just to show you what it looks like) notice in the pic it says 30hz at the top? Well it says that in PD2 and C2, even though it's at DP1.2.

Any help with this would be greatly appreciated, if you need any more info I would be happy to give it. Thanks in advance.