1.13 Real-Time Clock Subsystem; 1.14 Hardware Management Subsystem; Hardware Monitoring And Fan Control; Fan Monitoring - Intel DH55TC Specification

1.13 Real-Time Clock Subsystem

A coin-cell battery (CR2032) powers the real-time clock and CMOS memory. When
the computer is not plugged into a wall socket, the battery has an estimated life of
three years. When the computer is plugged in, the standby current from the power
supply extends the life of the battery.
The clock is accurate to ± 13 minutes/year at 25 ºC with power applied via the power
supply 5V STBY rail.
NOTE
If the battery and AC power fail date and time values will be reset and the user will be
notified during POST.
When the voltage drops below a certain level, the BIOS Setup program settings stored
in CMOS RAM (for example, the date and time) might not be accurate. Replace the
battery with an equivalent one. Figure 1 on page 11 shows the location of the battery.

1.14 Hardware Management Subsystem

The hardware management features enable the board to be compatible with the Wired
for Management (WfM) specification. The board has several hardware management
features, including the following:
• Fan monitoring and control
• Thermal and voltage monitoring
1.14.1

Hardware Monitoring and Fan Control

The features of the hardware monitoring and fan control include:
• Intel Quiet System Technology, delivering acoustically-optimized thermal
management
• Thermal sensors in the processor and PCH, as well as near the CPU voltage
regulators and system memory
• Monitoring of five system voltages (+5 V, +12 V, +3.3 V, Memory V-SM and
+V ) to detect levels above or below acceptable values
CCP
• Thermally monitored closed-loop fan control for all three fans that can adjust fan
speed as needed
1.14.2

Fan Monitoring

Fan monitoring can be observed via the BIOS setup user interface, Intel
Utilities or third-party software.
For information about
The functions of the fan headers
Product Description
®
Desktop
Refer to
Section 1.15.2.2, page 31
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