Talking Video problems with Cyanogenmod 10.1 on Galaxy Mini 2

Hey , BTW sorry if it's in the wrong place
I've upgraded my Samsung galaxy mini 2 to cyanogenmod 10.1 but the problem is that all the videos on Youtube or on my SD card are lagging ( yeah i don't know if it's a word) and it makes it NOT enjoyable at all , How can i fix this problem Please ?
Thanks alot.