Randomly, windowserver's CPU usage will jump to 50+%, and everything will start to stutter a lot. I've noticed this often when I'm viewing a website with Flash, but not always. Any idea why? It's very sporadic, which makes it hard to pinpoint the cause. I'm using Firefox 4.0, but it's not always when I'm using FF. Also, I'm plugged in and have the GPU forced to be on (using gfxCardStatus), which I thought would have more than enough processing power for WindowServer...