OCCT includes 6 different tests : OCCT and Linpack for your CPU, Memory for testing system RAM, 3D and VRAM for your Graphic card, and Power to stress your power supply. A monitoring engine is also embedded, to ease diagnostic and see how your computer reacts under heavy load using graphs. OCCT is great at generating heavy loads on your components ( CPU, GPU, Memory, GPU Memory & Power supply ), and aims at detecting hardware errors or stability issues faster than anything else. OCCT is the most popular all-in-one stability check & stress test tool available.