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The Open Hardware Monitor is a free open source software that monitors temperature sensors, fan speeds, voltages, load and clock speeds of a computer.

SpeedFan is a program that monitors voltages, fan speeds and temperatures in computers with hardware monitor chips. SpeedFan can even access S.M.A.R.T. info and show hard disk temperatures. SpeedFan supports SCSI disks too.

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

iStat is a series of system monitor apps. It's available in different versions: iStat Menus, iStat for iOS and iStat Server as a companion application to the iStat for iOS app that lets you remotely monitor your computers (free for Windows and Mac).

Real Temp is a temperature monitoring program designed for all Intel single Core, Dual Core, Quad Core and Core i7 processors. Each core on these processors has a digital thermal sensor (DTS) that reports temperature data relative to TJMax which is the safe maximum operating core temperature for the CPU. As your CPU heats up, your Distance to TJMax will decrease. If it reaches zero, your processor will start to thermal throttle or slow down so maximizing your distance away from TJMax will help your computer run at full speed and more reliably too. »

smcFanControl is the perfect application for all those Macbook owners getting burned by their hot-running Macbook.This Mac application allows you to control the speed of the fan in your MacBook so you can avoid it running hot.

WinBar is a free and compact program that lets you monitor your system and provides easy access to frequently used controls. WinBar will run on Windows 2000 and newer operating systems and is available in 32 and 64 bit flavors.

Lm-Sensors is a free and open-source application that provides tools and drivers for monitoring temperatures, voltage, and fans.

Personalize your experience with state-of-the-art real-time overclocking*. Used by world record setting overclockers across the globe, AMD OverDrive™ gives you unprecedented control over your processor, memory and chipset to push the performance envelope further than ever before.

Monitoring temperatures and status of system components such as CPU, GPU and hard disk drive, fan speeds

SysMetrix is a skinnable clock and metering application. Its purpose is to provide system metrics in a variety of interesting, useful, and cool ways. It can monitor and report on the hundreds of statistics

CoolBook is a tool for the MacBook, MacBook Air and MacBook Pro computers. It lets you monitor the frequency, voltage and temperature of the CoreDuo / Core2Duo CPU.

Corsair Link Dashboard software allows you to monitor your system and gives remarkable control over your case fans, lighting, and compatible Corsair power supplies and Hydro Series liquid CPU coolers that work together for optimal cooling and performance.

Professional System Monitoring Utility designed for Mac.