
W83627UHG
7.6.3 SMART FAN
TM Control
The W83627UHG supports two SMART FAN
TM I features—Thermal CruiseTM mode and Fan Speed
Cruise
TM mode—and SMART FANTM III. Each of these is discussed in the following sections. When
SMART FAN
TM I features are enabled, fan output starts from the previous setting in Bank0 Index 01h
and Index 03h.
There are two pairs of temperature sensors and fan outputs in SMART FAN
TM I, as illustrated in the
figure below.
Publication Release Date: March 24, 2008
-37-
Revision 1.44
Pin 90
CPUFANOUT
Pin 92
SYSFANOUT
CPUTIN
PECI_Agent1
PECI_Agent2
PECI_Agent3
PECI_Agent4
SYSTIN
CPUTIN
PECI_Agent1
PECI_Agent2
PECI_Agent3
PECI_Agent4
Pin 90
CPUFANOUT
Pin 92
SYSFANOUT
CPUTIN
PECI_Agent1
PECI_Agent2
PECI_Agent3
PECI_Agent4
SYSTIN
CPUTIN
PECI_Agent1
PECI_Agent2
PECI_Agent3
PECI_Agent4
Figure 7-9 FANOUT and Corresponding Temperature Sensors in SMART FAN
TMI
7.6.3.1. Thermal Cruise
TM Mode
Two pairs of temperature sensors and fan outputs in Thermal Cruise
TM mode:
SYSTIN and the temperature sensor selected by Bank0 Index 4Ah, bits 7 ~ 5
CPUTIN and the temperature sensor selected by Bank0 Index 49h, bits 2 ~ 0
Thermal Cruise
TM mode controls the fan speed to keep the temperature in a specified range. First, this
range is defined in BIOS by a temperature and the interval (e.g., 55
°C ± 3 °C). As long as the current
temperature remains below the low end of this range (i.e., 52
°C), the fan is off. Once the temperature
exceeds the low end, the fan turns on at a speed defined in BIOS (e.g., 20% output). Thermal
Cruise
TM mode then controls the fan output according to the current temperature. Three conditions
may occur:
(1) If the temperature still exceeds the high end, fan output increases slowly. If the fan is operating
at full speed but the temperature still exceeds the high end, a warning message is issued to
protect the system.
(2) If the temperature falls below the high end (e.g., 58
°C) but remains above the low end (e.g.,
52
°C), fan output remains the same.
(3) If the temperature falls below the low end (e.g., 52
°C), fan output decreases slowly to zero or
to a specified “stop value”. This stop value is enabled by Bank0 Index12h, bits 5 ~ 4, and the
value itself is specified in Bank0 Index 08h and Index 09h. The fan remains at the stop value for
the period of time defined in Bank0 Index 0Ch and Index 0Dh.
In general, Thermal Cruise
TM mode means
if the current temperature is higher than the high end, increase the fan speed;