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. ;-)