Beryl need too much CPU resource

Beryl, as well as compiz, 3d desktop environment make vista looks too out dated.
but they need too much system resources especially in CPU.

my toshiba satellite 5100 has quite good hardware spec.
intel pentium 4 moble 1.6GHz and 1GB of RAM, Nvidia 440 Go (NV17).

but that cannot satisfy the need of linux 3d desktop environment.
RAM and VGA reach the level of optimizing with several system mod, but CPU load cannot be optimized.

AS it shows in capture video, whenever beryl visualization effect was used, CPU usage goes to 100%.
These too much CPU usage make system much slower than normal gnome metacity environment.