Virtualmin has a background process called `collectinfo.pl` that is run by default every 5 minutes from Cron, to collect information used for the System Information page and historical graphs. If this is too often for your system, you can increase the gap between runs to up to 30 minutes using this field.

Alternately, select Never run to turn this process off completely. If you rarely login to Virtualmin's web interface as `root` and never look at the graphs of CPU load and other statitics, this option will reduce the CPU load on your system. However, it will cause the System Information page to take longer to load.