I have noticed on a few films the current being a 720p MKV that I get a little slowdown now and again, i'm running a wired network to a D-link DNS 320.
It lasts for a second and then its back to normal, really quick. Looking in the debug mode the cpu is around 30%.
The boxee is on the latest firmware
File size : 5.69 GiB
Overall bit rate : 6 899 Kbps
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
I have also noticed that when I have the boxee to match the refresh rate of the video it takes two or three seconds on load to switch, the screen goes black about 3 times. Then if I look at the video info it does this again to show that and again on exit back to the video.