[DCP-o-matic] multithreading while playing J2K...

There is a compute thread setting in DOM that is used for J2K encoding. In think one of the more recent code improvements was to do J2K DECODING while playing DCPs multithreaded as well. While I appreciate that I have 0 dropped frames in the player at 1/4 res, I notice that my 4core/HT MacBook only uses 4 threads while playing. And even these are only loaded 50%. I am nearly sure this machine could do at least 1/2 res decoding, without dropped frames, if not full res. Is there a way to improve this? How does the stand alone player decide how many threads to use? Or is OS X doing the thread distribution? Wouldn't it be useful if DOM (main app) would use 1/4res when playing DCPs in preview as well, and per default? The preview window is probably not much larger in most working environments anyway. - Carsten