IBM Intel Xeon X7350 44E4243 Data Sheet

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Document Number: 318080-002

The DTS (Digital Thermal Sensors) provide an improved capability to monitor device 
hot spots, which inherently leads to more varying temperature readings over short 
time intervals. The DTS sample interval range can be modified, and a data filtering 
algorithm can be activated to help moderate this. The DTS sample interval range is 82 
us (default) to 20 ms (max). This value can be set in BIOS.

To reduce the sample rate requirements on PECI and improve thermal data stability vs. 
time the processor DTS also implements an averaging algorithm that filters the 
incoming data. This is an alpha-beta filter with coefficients of 0.5, and is expressed 
mathematically as: Current_filtered_temp = (Previous_filtered_temp / 2) + 
(new_sensor_temp / 2). This filtering algorithm is fixed and cannot be changed. It is on 
by default and can be turned off in BIOS.

Host controllers should utilize the min/max sample times to determine the appropriate 
sample rate based on the controller's fan control algorithm and targeted response rate. 
The key items to take into account when settling on a fan control algorithm are the DTS 
sample rate, whether the temperature filter is enabled, how often the PECI host will 
poll the processor for temperature data, and the rate at which fan speed is changed. 
Depending on the designer’s specific requirements the DTS sample rate and alpha-beta 
filter may have no effect on the fan control algorithm. 

The Intel

®

 Xeon

®

 Processor 7200 Series and 7300 Series obtains its PECI address 

based on the processor APIC ID[4:2] at power on. APIC ID[4:3] is also known as 
Cluster ID[1:0] and APIC ID[2] is also known as Agent ID[1]. Cluster ID[1:0] is set by 
the chipset driven power-on configuration (POC) signals A[12:11]#. 

how the Agent ID is generated for each of the die based on the BREQ# signals asserted 
during power on for the Intel

®

 Xeon

®

 Processor 7200 Series and 7300 Series.