[BritBloke]

I played back a 1080p mkv over SMB share on wired network. I didn't notice the judder issues that other people talked but I did notice that it needed to stop for buffering every 30 seconds or so. So I guess that makes it pretty much unwatchable. I'm not sure how many Mbps the file was, it was on my atv2. Sorry I don't have much info I'm just trying to get more info out to the community.

I wonder if it's a RAM issue in your case? The ATV2 only has 256MB, whereas the iphone 4 has 512MB.

I just tested on my phone and with no other apps running, started XBMC and went straight to System Info. XBMC reports 40% memory used, so I'm guessing that would be closer to 80% on the ATV2, maybe less as you won't have the same memory usage as the phone with all it's radios, etc.

EDIT: I ran a 90MB 1080p MKV 1 min sample file, and while it was playing I checked Sys Info again (gesture was swipe left while movie is playing to get to the menu) and my RAM usage went up to 54%.

EDIT 2: I'm now streaming a movie from Navi-X and Sys Info is showing 41% memory usage. Pretty impressive!