Sorry for driving this thread away from where it started (we should probably continue under the 100% CPU heading), but this is just a supplement for my observations about triggers, so you has as complete a picture as possible. I was performing that trap sequence again, just to gauge how reliable it is. Scribbled in gimp Switched to Activity Monitor. Waited 5 minutes -- nothing happened The screen went blank and stayed blank for 40 minutes -- nothing happened I thought it was one of those failed experiments, and was about to start a new one. Then, I touch the key on the keyboard, the screen lights up, and the first thing I see is CPU load for X11.bin going from near 0 to 100% I've been bumbling around with this long enough to assert this was not random. The likelihood of coincidence was near zero, especially if you consider what happened next. Next, I began typing this message on another machine. The screen on the mac went blank again (I set it to turn itself off in 1 minute), and X11.bin continued to run 100%. I did not change focus -- Activity Monitor still has it -- I just woke up the streen, and now it turned itself off on its own, and could hear the fan and saw X11.bin at 100% from this other machine. Then, as I was about to finish what I was going to say about X11 going nuts with the screen turning on as well as turning off, I touched the key again and the screen lit up. X11 stopped spinning -- the effect I could so far achieve only by touching one of the X11 clients. I don't know if this makes the picture more clear or muddies it even further, but now it's a more complete picture. These machines have become as complex as all things in Nature. ... At this point, a friend sent a message to my skype on the mac (I heard a beep), making me touch the screen, which went blank a few minutes ago, and we're at 100% again. The trigger is not random. Access to it may be. ... many minutes and serveral screen-blanking cycels later, X11 is still running at 100%. I avoided touching it. So the conclusion for now is that the condition is stable, but can be disrupted by activity in X11. It can also be disrupted by other things (such as screen turning off or on). And it can also be precipitated by the same events, except for normal user events in X11, which only disrupt it. I don't know what to think. Must call it a day. --Gene