World of Warcraft
Run in DirectX mode instead of OpenGL
Unless you absolutely need to you should let the game run in OpenGL mode which it will by default. OpenGL is passed directly from WoW, through Crossover, to the native Linux OS and should be the fastest and most compatible rendering.
Open the config.wtf file in a text editor and remove any gxApi entries (i.e. SET gxApi "opengl"). Removing these entries will cause the game to run in DirectX mode instead of OpenGL.