BDM-610000050 Rev A Chapter 4: Using the cpuModule 65
Thermal Management
The cpuModule has several thermal features which can be used to monitor and control the board’s temperature
when extreme operating conditions are prevalent.

Thermal Monitor and Thermal Throttling

The Intel ® Thermal Monitor is a feature on the CMX58886CX that automatically throttles the CPU when the
CPU exceeds its thermal limit. The maximum temperature of the processor is defined as the temper ature that
the Thermal Monitor is activated. The thermal limit and duty cy cle of the Thermal Monitor cannot be m odified.
The Thermal Monitor can be disabled by the BIOS for applications where deteministic speed is more important
than device failure due to thermal runaway.
In addition to the Thermal Monitor, conventional Thermal Throttling is also provided. This forces the CPU to skip
clock cycles when it exceeds a thermal limit. The thermal limit and duty cycle of thermal throttling can be
modified in the BIOS, where both the PCB and CPU temperature can be set to activate thermal throttling . The
CPU and PCB temperature are displayed in the Thermal section of the BIOS setup..

Fan Mode

The CPU fan can be controlled by the CPU when connected to the switched fan power connector (CN15). Two
fan modes are supported, which can be toggled in the BIOS setup.
•Always On: When in this mode, the fan is always powered by the CPU.
•Auto: This mode allows the system to keep the fan turned off unti l the CPU is hot. When the fan mod e
is set to auto, the CPU’s power consu mption is reduced.

Further Temperature Reduction

The cpuModule’s temperature is directly related to power consumption. Reducing the power consumption of
the CPU will have an effect on the CPU’s temperature. Suggested methods for reducing the CPU’s power
consumption can be found in the Power Management section on page66.
Note The CPU and PCB temperatures displayed in the BIOS are approximate and should not be used to
validate a cooling solution.
Note If the CPU fan is connected to the continuous +5 V fan connector (CN14), changing the fan mode
options in the BIOS will not affect the fan, as it will always be turned on.