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106
Datasheet
Balanced Technology Extended (BTX) Boxed Processor Specifications
In addition, Type I TMA must be used with Type I chassis only and Type II TMA with Type II
chassis only. Type I TMA will not fit in a Type II chassis due to the height difference. In the event
a Type II TMA is installed in a Type I chassis, the gasket on the chassis will not seal against the
Type II TMA and poor acoustic performance will occur as a result.
8.3.2
Variable Speed Fan
The boxed processor fan will operate at different speeds over a short range of temperatures based
on a thermistor located in the fan hub area. This allows the boxed processor fan to operate at a
lower speed and noise level while thermistor temperatures are low. If the thermistor senses a
temperatures increase beyond a lower set point, the fan speed will rise linearly with the temperature
until the higher set point is reached. At that point, the fan speed is at its maximum. As fan speed
increases, so do fan noise levels. These set points are represented in
Figure 8-8 and
Table 8-2. The
internal chassis temperature should be kept below 35.5C. Meeting the processor’s temperature
specification (see Chapter 5) is the responsibility of the system integrator. Note:
The motherboard must supply a constant +12 V to the processor’s power header to ensure proper
operation of the variable speed fan for the boxed processor (refer to
Table 8-2) for the specific
requirements).
Figure 8-8. Boxed Processor TMA Set Points
Lower Set Point
Lowest Noise Level
Internal Chassis Temperature (Degrees C)
X
YZ
Increasing Fan
Speed & Noise
Higher Set Point
Highest Noise Level