MPEG4 (XVID) playback issues.

[Pihkal]

Well,it does happen mostly when the full screen has to get updated.
First i also thought it was caused by the lack of cpu-power,since mpeg4 isn't hardware accelerated,however when i ssh into the pi and run htop it shows around 50% cpu usage so there's plenty cpu power available.
My Soc is oc'd,the arm is doing 1050 Mhz,the core is running at 525 Mhz,the oc is stable,tested playing quake 3 in raspbian so this should also be ok.
I never use subtitles,and i've disabled them in the audio settings,no change..