Sometimes, when using the DirectX renderer, sublime text's processor usage will spike to 80-90% and begin to respond very slowly. After this occurs, any time I interact with sublime text (typing, selecting, interacting with the mini-map, mousing over the tab area, and perhaps other interactions), it will spike again. Sometimes, but not always, restarting sublime text will resolve the problem.
It's unclear to me what the trigger for this state is: it doesn't appear to be associated with other programs I'm running, but that's just from some cursory testing (e.g., kill all my user-bound programs and restart ST, and the problem sometimes remains).
I'm running the 20100119 beta at present, but have seen this going as far back as August.
I'm on XPSP3 with an ATI FireGL V3100 running dual displays. My drivers are up-to-date.
The OpenGL renderer alleviates this problem, but then I am subject to this problem with transparent windows (as well as generalized transparent window weirdness, even when the windows aren't overlapping).