Security Monitor Pro is relatively efficient with both CPU and RAM usage. The CPU usage depends on the resolution being captured from your cameras. For a 640x480 capture with 8 cameras, a Core i3 with 4GB of RAM is sufficient and a Core i5 is recommended. If you are capturing higher resolution such as 1280x1024, I suggest using at least a Core i5 processor with 8GB of RAM. You can use the evaluation version to test your cameras and CPU usage.