Flash Full Screen SLOW

I’ve got a custom FLV video player that I’ve
setup with a true full screen popup similar to
that of YouTube’s.

When the video is in the normal browser mode
the CPU load runs up to like 1 - 2% max. However,
when I make the video jump to full screen mode
the CPU load skyrockets up to 15 - 20% and just
sits there for the entire video.

I didn’t add any extra functionality for when the
video is in full screen mode so I’m baffled as to
why the huge jump in CPU load occurs. Also,
the memory rate stays virtually the same in normal
and full screen mode.

Any ideas?