playing x264 bluray mkv file video/audio not synch

i have ati radeon 3850 hd 256mb ram ddr3 using bsplayer to watch mkv files and some bigger movies and small gb i got video unsinched to audio and i get some movies to freeze, and on mediaplayer classic i cant even watch those movies please note movies are encoded as x264 i have corequad 2.4 and 4gb ram can someone point me whats wrong why i cant play with mediaplayer classic? also will mediaplayer classic support srt/sub subtitles? what to use so i wont have such problems? what is dvxa and how to rip bluray and encode with such codecs? thanks

Describe your process for making these BluRay movie MKV files. Maybe you are causing the problem when encoding.

i got them otherway, not making them. thanks