Q, MY SL is all busted up, lagging blah.
A, as of ball park jan 2012, try turning off your voice over IP.
At current updated drivers, with the latest patch release my much older viewer 2, became unplayable. when it was smooth around xmas. noteing the lag and the latest patch sitting there i figured i should grab it. Still unplayable. When investigating further found Vivox was going stupid, and also effecting computer proformance out side of SL only when SL was running. Turned it off. Became instantly smooth again... YAYA new feature FREE lag button. It might be my gigbyte board, my realtek ob sound card, just having compatability issues. With what ever has occured with the vivox portion of SL. But holy hell vivox in SL is not liking my system. turn it on isntant unplayable 2 fps no textures load, full chop.
me>preferances>sound media> 5th odd slider down voice over IP, at the end of it is a mute speaker and a turn off check box.
might not help everyone but helped me
this seams to be the problem, for me that is
Voice Server Version: Vivox Built with MSVC version 1600