After booting my PC this morning I've noticed that crossfire running with Vsync causes my games to run terrible unsmooth. It's not like microstutter, it's just a plain low frame rate look. Fraps registers DiRT 3 running at 60FPS with Vsync on, but it looks terribly unsmooth, so I turn off Vsync, all is good, apart from tearing. I tried Portal (original) with Vsync and it seems to go to 120fps rather than 60, but it does look smooth even with Vsync on.
My problem is near exact to the guy here yet the solution didn't work for me.
Dirt 3 and other games used to run nicely, but now it 'looks as if' they vsync at 30fps, instead of 60fps. It seems logical that games that sync at 60fps look like 30fps yet ones that sync at 120fps look like 60fps that this isn't a coincidence. I have no idea why this is happening, but I hope some of you can point me in the right direction.