Slow wired network

I use my NAS as a storage for movies.  When I use the WD TV Live Hub to play a movie; it stutters. 

When the movie is on the local drive - there is no problem - so it has to be a network problem. 

Could it be a problem with the cables? I didn’t have the problemen until I installed the latest firmware. 

Personally, i would ‘Rollback’ to the Previous Firmware Revision that Worked for you.