Hello, I have been playing since AA with no problems at all. But since two days (before the maj), I am experiencing an issue in game with the nameplate on :

http://imageshack.us/photo/my-images/10/oyq2.png/

If I turn off nameplate in the settings the bug is completly gone, except that if I alt+tab on windows and go back on game it often displays severe graphic bugs:

http://imageshack.us/photo/my-images/19/vbi4.png/

And this can go off if I alt+tab multiple times and finally the game is fine again.
So basically, this bug came from nowhere, I was playing just fine for a week with 0 bugs, I alt+tab and come back and this happens. I did not touch anything anywhere.
I've tried to do everything I could think of, I obviously restarted my pc, reinstalled the game, updated my graphic drivers.
But I do not know what to do to fix this, other games are working just fine (WoW, LoL, SC2 exct...) :

http://www.3dmark.com/3dm/1178031

Nothing seems to be wrong with me settings.
So I need some help