For performance testing, I have turned off vsync, and discovered this strange behaviour, I wasn't aware of before :
When my app starts, it runs at 600+ fps, which seems nice
when I give focus to another app, it stays at the same value
when I give the focus back to my cocos2d app, the fps drop to 70-90 fps. This is corrected by dragging the window around (the fps rise up to 600+).
Is this a known issue ? Is there a solution ?
I'll provide an example if needed.
I'm running cocos2d 0.5.0 and pyglet 1.1.4 on windows 7.