I can also confirm this issue, gnome-shell hits around 80% CPU usage on one core when running glxgears, It also causes stuttering in all games I have tried as well. Reverting the patch mentioned by Hussam brings the CPU usage back down to normal levels.
I can also confirm this issue, gnome-shell hits around 80% CPU usage on one core when running glxgears, It also causes stuttering in all games I have tried as well. Reverting the patch mentioned by Hussam brings the CPU usage back down to normal levels.