I am running Version 3.0.8500.0 on a Ubuntu server. When I play certain channels I get a lot of pixelating. I am using an HDHomeRun Prime with Comcast. It appears to happen when the channel is originally encoded as MPEG 2 from Comcast (e.g. ESPN HD.) I don't see pixelating if the channel is originally encoded as H.264 coming from Comcast. I don't know if the pixelating is caused by a problem transcoding from MPEG2, or if it is just a problem because MPEG2 requires much more bandwidth, or if there is some configuration problem with my Emby server.
I am running tests over a Gigabit ethernet connection so I don't think bandwidth in my house is a problem. I don't think it's a horsepower problem with my server since I can reliably record movies from live TV using Plex.
Playback using the HDHomeRun software (on a Mac) has no pixelating.