I've been looking into this and while this didn't work for me on my 650M, it may circumvent your CPU problem. I've attached a zip with reg file inside for you to try. This disables the compatibility checks in NvStreamSvc.exe.
I've got a larger writeup of my findings in the thread: "A quest to stream from mobile Kepler" (admittedly I didn't see this thread before posting mine).
Good luck!
EDIT: You'll need to either restart the "NVIDIA Streamer Service" in services.msc or just reboot your machine after applying the reg file for the changes to take effect. This won't change what GFE says about your configuration, but GFE isn't the one actually doing the compatibility checks for real