A CPU test examines the hardware specifications, temperature range and stability of a central processing unit in a computer. It first detects the CPU of the system and then puts it under a heavy workload to see whether or not it overheats.
Processors slow down when not busy and speed up to full capacity when under heavy workload to cater to the user's needs at minimal energy cost. On the other hand, the faster a processor runs, the more heat it produces. While the exact temperature depends on the individual processor, CPUs cannot handle heat above certain amounts. When the heat sensors detect that the CPU is nearing dangerous levels, the CPU slows down in order to cool off, regardless of the workload.
While defensive measures can save the CPU and the whole system from failing, a CPU that slows down when it should work at full capacity cannot fulfill the user's needs. As such, using a CPU test to determine whether or not the processor can handle heat can help the user identify potential heat issues and take countermeasures. Applying a new and more potent thermal paste and cleaning dust from the fans are two ways of reducing CPU heat.
HeavyLoad is a free CPU test that sends a stream of complex commands to the CPU with the intention of putting a heavy workload on it. The CPU responds by working at full capacity. If the CPU cannot maintain working at full speed, it indicates that the CPU overheats.