Youtube effect gameplay?

[Jasonz]

This can be caused by two things: One, your video card is handling the hardware acceleration of the video and combining that with P99 is causing issues. Or, your Internet access isn't fast enough to handle it without any problems (possibly wireless issues).

Either way, if you play your youtube videos at a lower resolution it should either completely fix it or at least improve it (click the little gear a the bottom right to change it).