The Matroska Media container is a very popular, open standard Multimedia container which is usually found as .MKV files. It is a very popular format in enthusiast circles and can be played directly in VLC or Windows Media Player with suitable codecs installed.
We played our 1080P MKV rip of The Dark Knight using the latest version of VLC Media Player.
The AMD FX 4170 CPU isn't best suited for media playback purposes, as proven by its 19% utilisation when playing our 1080P MKV movie. We would have liked to see this figure under 10%, but in all honesty, 19% CPU utilisation won't cause issues if media playback is part of a set of basic tasks that will be running on the system at any one time.