MKV files over a wireless network stutter

Thanks for all this information guys.  I have a question.  I was having the same problem with my player so I installed serviio, it seemed my problem was solved last night, everything was working fine, movies playing without studder.  Then I come home tonight and fire everything up and the problem has returned mysteriously overnight even when using serviio.  Are there any settings I could be missing or something I did wrong to make it change day to day like that?  Thanks for any help.