Ok hapklaar dan.. Ga naar Launchpad, klik andere, klik Terminal..
voer in: top -o cpu
That's it
"top: Find the CPU hogs in your system
The top command is familiar to Linux and Unix users. It lists the busiest programs running on a system, helping you determine why a system might be running slowly. Apple's graphical Activity Monitor application does the same, but top gives you a quick look without leaving the command-line environment.
By default, top displays the first 20 programs in its list. The problem is that, for some reason, OS X's top sorts its list not in order of descending CPU usage but in order of descending process ID. To get the list in proper CPU usage order, add the -o cpu) option, as shown below. The top list also shows which programs are running and which are "sleeping" -- waiting for input/output operations to complete. When a system is slow, top usually reveals the culprit."
NRG