Open Hardware Monitor - Monitors temperature sensors, fan speeds, voltages, load and clock speeds, with optional graph.

CPU-Z - CPU-Z is a freeware that gathers information on some of the main devices of your system : Processor name and number, codename, process, package, cache levels.

HWMonitor - HWMonitor is a hardware monitoring program that reads PC systems main health sensors : voltages, temperatures, fans speed.

SpeedFan - Hardware monitor for Windows that can access digital temperature sensors located on several 2-wire SMBus Serial Bus. Can access voltages and fan speeds and control fan speeds. Includes technical articles and docs.

GPU-Z - GPU-Z is a lightweight system utility designed to provide vital information about your video card...

Real Temp - Real Temp is a temperature monitoring program designed for all Intel single Core, Dual Core, Quad...