Windows XP32, JDK7 b142, JavaFX b27

Launch the colorful circles demo app either from the command line (java -jar) or by double clicking the jar file. The system becomes extremely sluggish (Core I5, 520M processor, 3.4gb ram)

Interestingly, the windows task manager shows very little cpu being used by the java process, but ~20% used by a process called "system".