This had been occurring off and on with the LoR stuff up until day before yesterday, but had stopped since. After today's character wipe and patch, there is a LOT of lag in both visuals and sound in places. However, it does not occur with my other characters (that were copied to Tribble again today), and is not consistent, even in the LoR sequences: sometimes there is a lot going on graphically, and it's fine; other times the toon is moving down a corridor without much around, visually, and there's a ton of lag.
Again, all on Tribble with my other toons is fine: no lag, no stuttering. Seems to only be the LoR stuff, and only again since the patch.
(...actually active since November 2010, which may one day be important to archaeologists, but not to anyone else...)