SpeedFan

The software is simple and straightforward: it monitors the temperatures of your computer components to help prevent overheating. It reads the hardware monitor chips found on most motherboards, and with the help of the user it can adjust fan speeds accordingly. SpeedFan can handle many kinds of monitoring, from motherboard sensors and hard disks to PWM fan controls, voltage readings and more. Although it's relatively simple to use, it works best for someone who has a little knowledge of PC hardware. This simply means that you need to understand what temperatures are normal when specific components are under load, but if you are new to it, the monitoring features alone are safe to use. It's a simple way to better your PC experience and maybe even extend its life by keeping it properly cooled.

Features:

• Can manually or automatically change fan speeds according to temperatures on supported hardware.
• Reads S.M.A.R.T. data and hard disk temperatures to warn about failing drives.
• Monitors temperatures, voltages and fan speeds of the sensors you choose. 
• Automatic warnings when temperatures pass the limits you set. 

SpeedFan helps prevent overheating and reduce fan noise by adjusting fan speeds according to system temperatures.

This software can be extremely useful and has many automatic and manual features that benefit those who use it. It is a good way to prevent your PC from overheating and to lower fan noise when the system is idle. It can take a little time to find out which sensor belongs to which fan, but once it is configured it is very beneficial to the life of your PC. SpeedFan also draws charts of the readings, can run actions on events, and on some hardware it can even change the FSB clock. It is freeware, works on Windows from Windows 9x to Windows 10 including 64-bit editions, and has not been updated since version 4.52, so newer hardware may not be fully recognized.