Wine-Staging Performance Regression since 2.0rc6

[Bjoern Bidar/Thaodan]

Hello guys I hope this is the right place to ask.
Since after 2.0rc6 many Wow user getting worse performance.

For comparsion: 
2.0rc6: 65fps
2.1/2.2: about 40
2.4: no change either even the main menu lags when you look close.

To test just download the game and open it even the main menu lags as said 
before.

Me and many users don't know how to help in debugging the issue, so im asking 
here.

Greetings

Björn