When I make a screenshot in OS X using command+shift+3, my system becomes unresponsive for about half a minute. I can move my cursor around, but that's the only thing that seems like it's alive at that point. I can click stuff, enter keyboard shortcuts, but it seems like they only get processed 30 seconds later, after the freeze. My configuration is 2,8ghz MBP with 4GB RAM ... so this shouldn't be a problem, system-wise. (better performance setting in the energy preference pane) This only happens when my system is running for a few hours though. But still, a few hours of uptime (less than a day) should not be a problem at all. I used to keep my C2D MacBook (Tiger) running for a few weeks and I noticed little to no decrease in performance. What gives?