What are Temperature Monitor and Hardware Monitor?

The programs Temperature Monitor and Hardware Monitor are part of an application suite for the Mac OS X operating system.

The applications make it possible to read out all available hardware sensors in Macintosh computers, to process their measured values, and to store them. The application Temperature Monitor is available for free, but is limited to accessing temperature sensors only. The application Hardware Monitor on the other hand is not gratis, but can access additional sensors if your computer is equipped with them. This includes the following sensor types:

Moreover, the applications can display additional technical information about your computer. Among other information this includes:

Of course the applications can read out the data only if your computer is equipped with the necessary sensors, and if Mac OS X can access them without needing third-party device drivers. Beginning in summer 2002, Apple has begun to massively drive forward the use of monitoring probes in the PowerMac series, the Xserve series, and in portable computers. Some models are equipped with 90 and more sensors. But Temperature and Hardware Monitor can detect sensors on many older systems as well if they are available.

We try to detect all sensors on as many Macintosh computer types in the support time range (see below) as possible. However, a prediction which sensors are available in which models is not possible, because Apple very often releases "silent product updates", where the hardware equipments of some models are changed but the names are not (specifications are "subject to change without notice"). The particular graphics card and hard disk configuration used is also important because these parts can include independent sensors, too.

Please note that Apple does not support an official or standardized way of reading out sensor data in Mac OS X (the only exceptions are the Server Monitor application for the Xserve series, and the IPMI support of the LOM-processor of Intel-based Xserve systems). Moreover, there is no documentation or other technical note about the individual function of the sensors. For this reason, the development of Temperature Monitor and Hardware Monitor is very costly because the necessary data has to be determined by reverse engineering and tests run on a variety of computer models. Please support the development of the applications by purchasing a registration key for Hardware Monitor.

Additional applications

The distribution packages not only include the full versions of Hardware Monitor and Temperature Monitor but also two additional variants of the software:

Another application, the add-on Hardware Monitor Remote allows you to monitor remote computers as well, transferring the sensor data over a network. The following table summarizes all available variants of the applications:

Application Name Part of download package Description
Hardware Monitor Hardware Monitor main program with all features
Hardware Monitor Lite Hardware Monitor version running in the menu-bar only
Hardware Monitor Remote Hardware Monitor Remote "agent" program running on remote computers in a network
hwmonitor command-line tool Hardware Monitor version for the BSD command-line of Mac OS X
Temperature Monitor Temperature Monitor gratis version of the main program, limited to displaying temperature sensors only
Temperature Monitor Lite Temperature Monitor version running in the menu-bar only, temperature sensors only
tempmonitor command-line tool Temperature Monitor version for the BSD command-line of Mac OS X, temperature sensors only

Data output and processing

The applications support the following operations on the measured readings:

Compatible operating systems and computers

Temperature Monitor and Hardware Monitor run with Mac OS X 10.4 or later. This includes system versions named "OS X".

Using the applications with Mac OS X 10.7, OS X 10.8, or later is possible, but not recommended. Apple's sensor drivers shipped with these operating system versions are very inefficient. They cause high CPU load and high energy consumption.

The applications are only designed for use with Apple-branded computers released between August 1, 2002 and October 31, 2012. They cannot be used with other model series.

All support for Temperature Monitor ends on October 1, 2014.

Table of contents