[maxmsp] 20% cpu load for MAX when doing nothing ???

Hi all

I currently use to run the activity monitor because I am working on a project involving a lot of display and midi computations and want to know what happens.

Even with not a single patcher loaded in Max, and just after starting both my macbook and Max, tha monitor shows sometimes a 20% to 30% activity for Max, sometimes much lower, a few %. It appears to be more or less random. The cpu load disappears when I close Max, even if no patchers have been loaded in the session.

Not a real problem, but I would appreciate to understand what is "sometimes" consuming power in the background, sometimes not. And perhaps is there something to tune in my own system (recent Macbook pro, 2*2,33 Ghz, 2 GB RAM, IAC driver on, Edirol midi interface UM1 plugged, MaxMSPJitter 456).

Regards

Dominique