This is quite a big question that tends to pop up from time to time. It is about CPU intensive system (and normal) apps that you have know idea why they are going flat out on your computer. This can be trouble some, and can happen quite often for no reason. This post is going to list some of the techniques I use to get my computer back to normal. They are sort of listed in order or completion. For example you go through the list one at a time. If you know of any more tips, please leave them in the comment.
1) Sit It Out
Probably the simplest and most obvious answer. If you find some random CPU process is go full hog and then you start fiddling trying to quit it, it could take long than just leaving it alone. My best recommendation is to leave your computer for 5-10 minutes, get a drink and see if the program has quit it’s self. Most do.
2) Quit The App In Activity Monitor
If you have sat out the application for 10 minutes and you are starting to get impatient (or you are on a laptop), you may have to quit the application. Open up activity monitor in Applications > Utilities. Select the applications (you can sort by CPU). Then press Quit Process on the menu bar and then click quit on the pop up box. You should try and quit it normal so the program can exit cleanly, you may have to wait a minute for the application to exit. You could damage important files if you force quit an application so always try a normal quit first.
3) Force Quit An Application
This is similar in method to the previous command except you press “Force Quit” instead of quit. Always try to quit an application normally, wait, and then try to Force Quit an app.
4) Terminal Quit An Application
At this point your getting a little desperate to quit this application. Your low on power if you are on a laptop, or you have wasted to much time waiting for the app to close normally and you need to get back to work. Quiting the application couldn’t be simpler. You need to have Activity Monitor open. The first step is to get the PID. This is the identifier for the process. If you don’t have a PID column go (in Activity Monitor) View > Columns > Process ID. Then in Terminal type the following:
kill PID 1234
It should then disappear. If that doesn’t work you can try:
sudo kill PID 1234
This will use admin powers to kill the process.
Alternatively you could try the following. This is useful if you know the name of the process or the tip above doesn’t work.
Where name is the name of the process. Again you could use sudo if it doesn’t work first time. Nine times out of ten this will work and you won’t need to do anything else.
The final step is to restart your computer. You have given up on all of the other steps. This rogue system process has gone to far.
Most of the time system process can be stopped by using one of the methods explained above. If a process continually uses up a lot of resources you have have to look into it. Good starting points include the Internet as well as your console log.