WinBar!

Rainmeter is a desktop customization platform. Through Rainmeter, you can enhance your Windows computer at home or work with skins: handy, compact applets which float freely on your desktop, much like Windows Sidebar gagdgets, or dashboard widgets for the Mac. Rainmeter skins provide you with useful information at a glance. Its easy to keep an eye on your system resources, like memory and battery power, or your online data streams, including email, RSS feeds, and weather forecasts. Many skins are even functional: they can record your notes and to-do lists, launch your favorite applications, and send your tweets to Twitter - all in a clean, unobtrusive interface that you can rearrange and customize to your liking. »

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

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

Core Temp is a compact, no fuss, small footprint program to monitor CPU temperature.

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.

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

AMD System Monitor is a comprehensive application which displays all the information about your system AMD products (and Intel CPU). It generally provides the overall functionality of GPU and x86 workloads.

Temperature Monitor is an application to read out all accessible temperature sensors in Macintosh computers. The program can visualize the history graphs of the readings, display measured values in a large variety of fashions, or announce readings by speech output. It can also store and export values.

Hardware sensors monitor utilizes sensor chips on smart motherboards to track system and CPU core temperatures, voltages and cooling fans. By quickly catching an overheated computer, you can prevent disasters such as system instability or damage. The program is resource friendly, resides quietly in the system tray, and continually monitors the various parameters. By clicking its icon, you'll view real time values for each component. Hmonitor supports all modern Windows versions: Windows 7, Vista, 2008, XP, 2003, 2000 ,NT4, including X64 editions. »

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.

CPU Thermometer is one free CPU temperature monitor; it can help you monitor your computer CPU temperature in live time. Program can start with Windows start-up, and show live CPU temperature in your desktop tray icon, so you get this important system information at a glance. This is one completetly freeware, easy to install and easy to use. CPU Thermometer will show CPUID, Frequency, Core Number and CPU current temperature. Program provide some useful functions, when the CPU temperature over some value that you set, it can "Show warning message", "Shutdown computer" or "Reboot computer." »