ST3 performance (i.e. scroll performance) on my rMBP is fantastic and a dramatic improvement over ST2.
However with ST3 on Windows the performance does not appear to have changed, that or there is frame limiting in the scrolling. And I don't see a message "using gpu buffer" in the console there either.
It really isn't a big deal on windows, because there isn't the really nice feedback possible (like with the Mac's touchpad), but it'd be nice if we could get the scrolling animation to match vsync.