Intel Xeon Processor with 800 MHz System Bus Thermal/Mechanical Design Guide

34 Intel® Xeon™ Processor with 800 MHz System Bus Thermal/Mechanical Design Guidelines
Thermal/Mechanical Reference Design
2.4.8 Reference Active Thermal Solution for the
Intel® Xeon™ Processor with 800 MHz System Bus
In addition to the 1U and 2U passive CEK heatsinks, Intel is developing an active version of the
CEK heatsink for the Intel Xeon Processor with 800 MHz System Bus targeted at workstation
chassis as well as server chassis which are 3U and above in height. All three heatsinks will be
offered as part of boxed Intel Xeon Processor with 800 MHz System Bus products. These solutions
are intended for system integrators who build systems from components available through
distribution channels.
The active heatsink is primarily designed to be used in a pedestal chassis where sufficient air inlet
space is present and side directional airflow is not an issue. The 1U and 2U passive
heatsinkheatsinks require the use of chassis ducting and are targeted for use in rack mount servers.
The retention solution used for these products is called the Common Enabling Kit, or CEK. The
CEK base is compatible with all three heatsink solutions.
The active heatsink solution for the Intel Xeon Processor with 800 MHz System Bus will be
transitioning after initial product introduction from a 3-pin thermistor controlled solution to a 4-pin
pulse width modulated (PWM)T-diode controlled solution. This transition is being done to help
customers meet acoustic targets in pedestal platforms, through the ability to directly control the
active heatsink fan RPM. To properly support this new active heatsink solution it may be necessary
to modify existing baseboard designs with 4-pin CPU fan headers. If a 4-pin active fan heatsink
solution is plugged into the older 3-pin fan header the heatsink will revert back to a thermistor
controlled mode. Please see the Section Chapter 2.5 Electrical Requirements section of this
document for more details.
Figure 2-14 is a representation of the active heatsink solution that will be offered as part of a boxed
Intel Xeon Processor with 800 MHz System Bus.
2.4.9 Active Heatsink Weight
The 2U+ active heatsink solution will not exceed a mass of 1050 grams. Note that this is per
processor, so a dual processor system will have up to 2100 grams total mass in the heatsinks. This
large mass will require a minimum chassis stiffness to be met in order to withstand force during
shock and vibration.
Figure 2-14. Active CEK Heatsink 3-Pin & 4-Pin (Representation Only)