Okay, on closer inspection it is definitely maxing a single core at a ratio of 80% ST2 20% WindowServer (roughly).
Here's a sample when continuously scrolling: http://puu.sh/FILf
Out of curiosity I also did one for Safari 6, which makes use of QuartzCore instead of CoreGraphics: http://puu.sh/FIOY
Good luck on this one. Sublime already performs better than the other text editors I tried out there, but it would be amazing to see it be the first one to bring back smooth scrolling to coders using retina displays :).