Resizing a window in Vista pegs CPU

Got Vista? Try this:

That's right, CPU goes from 2% to 100% when simply resizing a window! Even with Glass/Areo turned off!

PC used: (Note: same happens on my x64 bit version on my Beefy desktop at home)
IBM Thinkpad Z60m
Vista RC2 5766 (x86)
1.73 GHz Intel Centrino M
1.27GB RAM

Crazy!!