RadiSys PL35Q, Product Manual, Page: 35 / 72

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System management
35
System management
The Q35 motherboard includes hardware system management functions using the Winbond
W83627DHG chipset. These functions include monitoring system voltages, monitoring
temperatures, and monitoring and controlling the system fan.
Voltage monitoring
Table 23 identifies the motherboard voltage rails that are monitored and explains how they are
used.
Temperature monitoring
Up to three thermal sensors can be used to monitor temperatures in the system.
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The first sensor measures the motherboard temperature, and is contained within the
W83627DHG chipset. This is a localized reading dominated by the motherboard surface
temperature around the component.
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The second sensor is located on the processor die to accurately measure the local die
temperature. Since the local die temperature fluctuates rapidly with activity, the controller
within the W83627DHG filters the signal to produce an average temperature.
There are temperature deviations across the processor die that cannot be observed by this
sensor. See Intel’s processor datasheet for further information.
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The third sensor can be connected to the remote thermal sensor header. This sensor should
be a silicon diode or transistor connected as a diode, such as a Fairchild MMBT3904 and is
used to measure temperatures of the external device connected to the motherboard.
Note: In the BIOS setup utility, you can set a CPU temperature overheat threshold in the
Advanced Features > Hardware Monitor menu. When this threshold temperature is reached, the
system BIOS will activate the alarm system.
Table 23. Monitored voltage rails
Voltage rail Usage on motherboard
+12V Fans, expansion slots
-12V
+5V Processor voltage regulator, internal voltage regulator for chipset and system memory,
internal logic, USB and video ports, expansion slots
+3.3V Internal voltage regulator for chipset and processor interface, firmware hub (FWH),
clock generator, system monitor, audio, internal logic, expansion slots
3.3Vsb 3.3V standby
VBat_RTC CMOS battery voltage
V
core
Processor core voltage
V_DIMM Memory voltage