I have heard it said that CPanel uses up a lot of system resources compared to other control panels. What exactly does this mean. Does CPanel only use the resources while someone is currently in CPanel. For instance, I am the only person on my server (dedicated) that can get into WHM and CPanel. So, if I am in them, it makes sense that they would be sapping resources. Do they also slow the server down even when I am not in them?
CPanel *cough* may not use a ton of resources in itself. It just installs everything under the sun and automatically starts them. If you are worried about resource usage I would recommend a more stable and less bulky control panel like DirectAdmin / ServerCP / LxAdmin. All of which are just as full featured without the CPanel problems.