I think I'm on to something but I'm not quite sure. I've upgraded my router and one of the wireless game adapters to N this week. I started running more shows on the HR20 with the N adapter but I'm still seeing studdering - on the local network shows only (channel 5 (NBC), 33 (CW)). I haven't gone back to look at all of the playback issues (and I'm going to list mine this morning sometime), but can you guys see a difference in playback of HD shows between the local and network shows? I'm not sure if it's just me or not but I find it pretty curious.