said by papapew:NEVER MIND...
I manually updated to Silverlight 5 and changed the optimum app icon to open the 64-bit version of silverlight instead.
(I changed the target from "Program Files (x86)" to "Program Files")
CPU is now 10-20% when running video!
Can anyone help me figure out how to "manually update to Silverlight 5"? My laptop is getting killed! Running Win7 x64, 2GHz P6100, 4GB RAM