The System Management Unit (SMU) is an advanced internal subsystem introduced in late 2004 with the
iMac G5
The iMac G5 is an all-in-one personal computer that was designed, manufactured and sold by Apple Computer from August 2004 to March 2006. It is the final iMac to use a PowerPC processor, making it the last model that could natively run Mac ...
and
Power Mac G5
The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and ...
series computers. It manages the functions previously governed by the
PMU (Power Management Unit) as well as additional cooling functions.
Overview
The SMU manages thermal and power conditions to optimize the power and airflow while keeping audible noise to a minimum. Power consumption and temperature are monitored by the
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
, which communicates the necessary adjustments back to the SMU. The SMU makes the changes, slowing down or speeding up fans as necessary.
Resetting the SMU may fix certain problems during
troubleshooting
Troubleshooting is a form of problem solving, often applied to repair failed products or processes on a machine or a system. It is a logical, systematic search for the source of a problem in order to solve it, and make the product or process ope ...
.
See also
*
Power Management Unit
The Power Management Unit (PMU) is a microcontroller that governs power functions of digital platforms. This microchip has many similar components to the average computer, including firmware and software, memory, a CPU, input/output functions, ti ...
(PMU)
*
System Management Controller The System Management Controller (SMC) is a subsystem of Intel and Apple processor-based Macintosh computers. It is similar in function to the older SMU, PMU, or UAE of non-Intel Macintosh computers.
Overview
The SMC has roles in controlling ther ...
(SMC)
References
* Owen W. Linzmayer (ed.). ''Desktop and Portable Systems: Second Edition''. .
Apple Inc. hardware
Macintosh computers
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