CPU stress testing is the process of testing a system, while the machine which is hosting the system has reduced CPU resources. Typically testers have a CPU stressor tool which runs on the side, chewing up CPU cycles. While this is going on testers run their regular functionality tests. This simulates what happens when a user of the system under test uses the system while several other programs are running on the host machine. In general there are three different kinds of CPU stressing. First, you want to use up as many CPU cycles as possible to see what happen when the system under test is starved for CPU time. Second, you want to have as many processes running as possible which will create lots of process-context switching to make sure there aren’t any strange timing issues. Third, you want as many process being created and destroyed as possible which creates lots of process-creation switching, again to uncover any hidden timing issues with the system under test.