Well I have a thinkpad T60p with 256MB ATI FireGL V5200, 2.16 dual core processor... so needless to say my laptop is capable of running windowfx.  However, upon setting it up and loading it to the system tray I noticed my CPU was being consumed anywhere from 50 to 100%.  Once I unloaded it my cpu dropped right back down to 4%.  I saw a similar problem with IconX, but I didn't see a fix.  Anybody have any tips as to what to do?