I have an HTPC with PLAY-ON Installed. The PC has Gigabit LAN and I have hardwire/LAN running from the router to all TVs. Still, when I stream HD rips (MKV of Blu Ray) the player on the TV shutters/skips. If I pause the pla-on media player for 30 minutes in the begining, then I can stream. I would prefer to find another solution so I on-demand for my library i.e. instant streaming.
My hard drive is external using USB 3.0 SS. That is not the bottleneck since I can watch HD perfectly on the LCD TV directly connected to the HTPC.