Comment 21 for bug 788607

I think there was either an overstatement or a misreading :) It is and will still be possible to deactivate compositing via the usual GConf key. I hope that clears it up.
In the meantime I think this matters deserves more investigation than just saying "it's the same issue as when using OpenGL composition". Metacity uses XRender to do the compositing and has very different code paths to Compiz. I know that ultimately it might be the same underlying issue with the hw/drivers but I believe it requires digging.