stuttering on geekbrief

im new to using zinc.so far its great. ive watched several shows on revision3 with no problem. when i watch geekbrief tv i get stuttering. with boxee,hulu,wmc,or browsers i have no problems playing video.

my internet download speed is on average 20mbps or 20MBps not sure which sorry lol but i pay big bucks for it so its a pretty good speed.best i can get in my area. i dont think speed is the issue. anyway i can adjust buffering settings

im using windows 7 x64 ultimate. dual core amd 4gb ra,...thanks guys!!!