fan

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).

HWMonitor for Windows® x86/x64 is a hardware monitoring program that reads PC system's main health sensors : voltages, temperatures, powers, currents, fans speed, utilization, clock speeds…

Real Temp is a temperature monitoring program designed for all Intel single Core, Dual Core, Quad Core and Core i7 processors.