Intel Pentium 4 (551) JM80547PG0961M User Manual

                                               

   

87

 

The boxed processor fan will operate at different speeds over a short range of internal chassis 
temperatures. This allows the processor fan to operate at a lower speed while internal chassis 
temperatures are low. If internal chassis temperature increases beyond a lower set point, the fan 
speed will rise linearly with the internal temperature until the upper set point is reached. At that 
point, the fan speed is at its maximum. As fan speed increases, so does fan noise levels.  Systems 
should be designed to provide adequate air around the boxed processor fan heatsink that remains 
below the lower set point. These set points, represented in Figure 35 and Table 38, can vary by a 
few degrees from fan heatsink to fan heatsink.

 

 

1.  Set points may vary ±1

°

C.

The internal chassis temperature should be kept below 40°C. When the internal chassis temperature 
increases above 45°C, the Thermal Monitor may become active (see Section 7.3). Meeting the 
processor's temperature specification (see Chapter 6.0) is the responsibility of the system 
integrator.

°

C)

36

When the internal chassis temperature is below this set 
point the fan operates at its lowest speed. Recommended 
maximum internal chassis temperature for nominal 
operating environment.

40

When the internal chassis temperature is at this point the 
fan operates between its lowest and highest speeds. 
Recommended maximum internal chassis temperature for 
worst case operating environment.

45

When the internal chassis temperature is above this set 
point the fan operates at its highest speed.