Hello.
I'm running VLC 1.1.6 (Intel 64-bit) on a core i7 4GB RAM Macbook Pro.
I saw I'm not the first to notice the following problem:
I open my mkv file, and it starts normally, but as it gets to the end it becomes choppy and almost all of the computer's memory is occupied. After I close VLC and perform a purge, everything goes back to normal. If I run the same file in Quicktime I have no such problems.