System Processes

[Malcor]

Does anyone know how I would go about making a script that I could run as a cron job that will check the system every 5 minutes for a process using over x% of the cpu or ram?   It would be preferable if we could make it note the id in a file and on the second check if the process were still running over X% then kill it.   Thanks for any help in advance   Scott Clifford