[Pharo-dev] Keeping Pharo CPU usage low: how?

I am currently experimenting with Pharo on Amazon EC2. I'd like to keep the CPU usage low for when Pharo hasn't anything special to do. At the moment, I see that Pharo uses 2-3% of the CPU when just blinking the caret. Is there a way to get that lower? Even if it means tweaking the VM. The OS is Ubuntu 12 LTS Thanks!