This paging method, if used in a multiplayer environment will break uru to the point that it will probably crash in many cases.
When Innocent Programming Goes Bad... coming soon to a shell near you (with MORE to come after that).
Also, if I have lots of objects which are animated at different times will this affect the lag - or is lag more to do with numbers of faces and numbers of simultaneous animations??
I'm pretty sure that if you play an insane amount of animations at once, the game will freeze up with lag or crash completely- an example of this would be (MORE/MOUL) Ae'gura filled to the brim with /dance-ing avatars, which you may have been unfortunate enough to encounter during Live >.>. It would be unlikley that you'd play enough animations at once to cause that amount of lag. Lag can also be caused by too many vertices, as you said. It's really about how much stuff, be it physics, lighting or animation, has to be computed (and/or sent over the internet) at a time by the server, and how fast that information can be interpreted. The more info, the laggier it gets.