While copying some biggish files onto a TrueCrypt volume, I was keeping an eye out for the CPU load, after upgrading to a new version. This view greatly surprised me: An X11 server running consuming 100% of a CPU? WTF? It turns out that there was another top process running on the X server, and its output caused the server to suddenly utilize 100% CPU. Just hiding the top (not quitting top) window immediately brought resources back down to normal. The morale of the story? Watch what you leave unseen. ;-)