I have a rpi3 and a rpi2 they are both running stretch. However my Rpi2 constantly stays at 100% CPU. It is also extremely slow executing commands from the terminal. I am using all 4 USB ports and camera on the rpi3 and it varies from 60% to 80%. The rpi2 is new I have had my rpi3 for over a year. Is this common? Can I do anything to decrease the CPU usage on the 2 for better performance?