Cron jobs must be scheduled so that they do not go off less than 5 minutes apart.
So, any one job can run every 5 minutes, not 4, 3, 2 or 1 minutes.
If you have two jobs, A and B
A can run at 0, 10, 20, 30, 40, and 50 minutes past the hour.
B can run at 5, 15, 25, 35, 45, and 55.
You cannot...