On a big project, with a lot of files, I’m seeing the same problem on OS X Mavericks. Fans blowing and all. Not in ST2, but it’s there in ST3, build 3047. For instance, when I rename a folder containing a lot of markdown files, sublime becomes unbearably slow for a while.
The funny thing is that it only started recently. I’ve been working on that project for a while without problems. I have tried disabling plugins, but that didn’t help. The only two other major things that are different since then are that I’m running Mavericks, and that I have encrypted my hard drive. I’m thinking it might have something to do with the latter?