OCCT (OverClock Checking Tool) will let you benchmark, overclock, and monitor your system components.
It comes with four built-in tests aimed at checking CPUs, GPUs, and Power supplies. OCCT will also monitor temperature, voltage, and fan speed and system constants such as CPU Usage, Memory Usage, and FPS.
Up to 16-core support ( for instance, up to a Quad-Kentsfield or an Octo-Conroe )
Customizable tests ( Duration, Priority, CPU or RAM, ... )
CPU and Motherboard detection
Monitoring support through 3rd party application ( i.e. MBM5, Speedfan and Everest Ultimate Edition 3.50 or above )
Can produce graphs showing temperature and voltages during the test : Unique feature !