SystemLoad : Put Mac Processors Under Heavy Load

SystemLoad is a small Mac utility that can put the system under heavy load. It does this by running multiple processes and threads under various processors and their different cores. When the processor is pushed to a high load, it becomes hot and you can observe the reaction of your system through the cooling fans and temperature sensors.

SystemLoad is useful when you want to know the behavior of your system under high load. When the processor is loaded with too many processes and threads, we can observer whether the cooling fans are working properly, whether the temperature sensors are showing the gradual rise in the CPU temperature and so on.

SystemLoad has a small window where we can see the total number of processor cores available in the system. We can choose how many of these cores are to be loaded. We should not choose all the cores for the heavy loading because it can result in momentarily unresponsive system. macOS will handle the situation eventually, but we should still avoid it. A safe number to use is 3/4th of your total number of CPU cores. For example, if your CPU has 8 cores then load only 6 cores maximum.


We can also choose to level of additional load to generate using a slider control. What this means is that if a CPU processor core is already loaded to a degree, then how much extra load should this application create for that core. We should keep this additional load to less than 80.

When SystemLoad stresses your CPU, you will notice that fan has started to spin faster for extra cooling. You can also observe the gradual rise in the CPU cores’ temperatures. We can examine if the cooling is being done properly and if there are some noises are coming out of the power supply unit or the fan unit. In case of the noises, the units have become faulty and needs replacement.

You can download SystemLoad from