Sometimes my kitchen TV and living room TV will be showing the same program from different sources, e.g. one is showing BBC1 from satellite through the Tivo and the other is tuned directly via terrestrial UHF. I usually notice a difference of about 3 seconds in the audio (the Sat/PVR lags), I know satellite lags terrestrial broadcasts but AFAIK the PVR causes additional delays too. I believe the latter is a side-effect of PVRs in general since they are playing a recording even if it's realtime you're watching and not all of this delay is attributable to the connection.