I got to go up in the Muse with Mordecai... what a lovely airship! (Note to all balloon/airship designers: please consider some models with loveseats...)
We ascended into the sky to look at the end of The Chain... and suddenly I noticed that the pan and zoom were insanely smooth. View>Statistics... and whoa! 25 fps!
I presume it's because at that height, there's very little to actually render; very few prims are visible, just as in Cheyenne's House of 1,000 Pleasures there aren't (or weren't, at the time she showed me around) many things present and we were in an enclosed area. Hence the sweet graphics performance on my humble Socket A Sempron 2400+ and nVidia 5500.
Would that SL were like that all the time! Sigh...