Compiz strangeness

I just bought a Asus P5E-VM board, sporting a nice G35 onboard Intel graphics accelerator, a Q9550 and 4GB of RAM running on latest (all updates installed) Ubuntu Hardy. I experience a dramatic drop of system power when using compiz. Is this due to EXA render acceleration not yet really supported in the 2.2.1 intel graphics driver or should I worry? ^^

I think you can guess when I turned compiz off 😉