The Open Hardware Monitor is a free open source application that monitors temperature sensors, fan speeds, voltages, load and clock speeds of the hardware of a computer. It runs on 32-bit and 64-bit Microsoft Windows operating systems using the Microsoft .NET Framework. Linux systems with Mono are supported as well, although the available sensors are (currently) very limited.

Supported Hardware:
CPU core sensors
Intel Core 2, Core i3/i5/i7
AMD K8 (0Fh family), K10 (10h family)

Mainboard sensors:
ITE IT8716F, IT8718F, IT8720F, IT8726F
Fintek F71862, F71869, F71882, F71889
Winbond W83627DHG, W83627DHG-P, W83627EHF, W83627HF, W83627THF, W83667HG, W83667HG-B

GPU sensors:
Nvidia
ATI

Hard disks:
S.M.A.R.T. sensors (optional)

Fan controllers:
T-Balancer bigNG (direct acces to USB-Serial driver, no T-Balancer Server needed)

User Interface:
Display of sensor value, min, max and (technical) limit (columns configurable).
Window position and size is restored the next time the application is started.
Sensor names can be edited (click sensor twice or select the sensor and press F2).
Plotting of temperatures graphs (currently limited to max 100min).
Display can be limited to certain sensor types (voltage, clock, temperature, fan).
Hard disk S.M.A.R.T. sensor reading can be disabled to allow unused disks to be turned off.
Minimize to system tray.