Original bug report (declined by debian) is http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=677470
I use kde 4.8, nvidia driver.
Number of programs use animated icons in tray. When icon gets animated,
/usr/bin/X eats up to 100% cpu. This includes psi instant messenger
(animates new message arrival), clementine music player (animates play
progress) and other.
Only /usr/bin/X gets affected with icon gets animated.
Few times I switched to console and run "gdb -p XORGPID", and always saw
"GetXIDRange" function in which X seats.