[Pharo-dev] Reducing the activity of the image

I have an installation where a pharo powered hardware is used in a closed case. Over time that collects quite some heat. One reason for this is that the pharo vm is taking approx. 6% CPU all the time. The only thing that happens is network/sockets. I suspended the ui thread in the image but on this platform it doesn't help. Are there any tweaks to lower the polling and the activity of the image/vm even more? thanks, Norbert