10.8.3 and rMBP - throttling GPU memory clock while Youtube

Hi there,

when I play a game the memory clock of the 650M goes up to 2508 Mhz, but when I start a Youtube video at the same time the clock is fixed to 780 Mhz and thus slowing down the game significantly.

When I start a render during gaming the GPU is still at 2508 Mhz during 100% CPU usage, but only Youtube slows it down badly.

What is this for a bad feature?