TalkingSoft.com Forums: Bad playback on some HD (720p mkv) movies - TalkingSoft.com Forums

Hey everyone,
I've got a problem I can't find a solution to.
Most of the HD movies (720p mkv) I have playback flawlessly, however some one them have terrible playback problems.

My rig is a:
P4 3ghz
1gb ram
6600GT 128mb

I would expect that my hardware is sufficient to playback the movies with out a problem (because most mkvs seem to work perfectly), just a handful of them are giving me trouble.
When I play them in VLC I get major frame drops/freezes
When playing them back in Media Player Classic there are no frame drops, but the audio/video goes out of sync (Video playback too slow)

I am hoping this is a codec/software issue more than it being a hardware related issue.

CPU usage during files which playback fine is around 20-30%, however
Files with playback issues cause my CPU usage to jump up and down between 5-60% (up and down like a rollercoaster)

Any help is appreciated =) thanks


(Just in case you are wondering, the I've tested the files with playback issues on my other pc, and they work fine there)