White Paper on Turbo Boost Using Low Power Processor

Products Update for Turbo Boost with Low Power Processor Support Update
2. Intel
®
Turbo Boost Technology support on
Intel server boards
2.1 CPU load current monitor (IMON) on Intel
®
Server Boards and
Systems are optimized for higher TDP processors
Per Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 11.1
Design Guidelines, IMON (i.e. CPU load current monitor) is an analog output signal (from VR to
CPU ISENSE pin) whose voltage level is proportional to the VR’s total output load current. The
VR regulation on the platform will provide gain setting to CPU during the Power-On
Configuration (POC) time. The accuracy of the proportional gain will be platform and processor
dependent. The accuracy of the IMON reporting and the optimization of the processor specific
IMON gain setting will determine Intel
®
Turbo Boost Technology performance on a particular
board or system. More accurate IMON reporting will have a positive impact on Intel
®
Turbo
Boost Technology performance.
Specific to the Intel
®
server boards and systems, the CPU load current monitor (IMON) settings
described above are optimized for processors with higher TDP specifications. As a result, some
lower TDP processors may not realize the full benefit from the Maximum Turbo Frequency. It is
expected that these processors may drop back to their marked operation core frequency sooner,
and the point at which a processor drops out of Turbo Boost is dependent on the constraints
listed above in Section 1.2. These processors include Intel
®
Xeon
®
Processor 3400 series with
30W/45W TDP and Intel
®
Xeon
®
processor 5500 and 5600 series with 40W/60W TDP.
2.2 Customer Impact and Action Recommendation
Intel
®
Turbo Boost Technology is a feature that adds extended performance to customer’s
applications. This Turbo Boost enhancement is most pronounced at moderate workloads where
the processor can achieve the maximum frequency boost. When all other conditions are equal,
higher CPU utilization rates, higher environmental temperatures or processors with lower TDP’s
will cause the system to drop from Turbo Boost mode sooner.
The Turbo Boost Technology support on Intel’s server boards and systems for the above
mentioned lower TDP processors has rather limited impact on the overall system performance
across typical workload; therefore Intel does not recommend any specific customer actions
when using the low TDP processors on Intel’s server boards and systems.
Revision 1.0Enterprise Platforms and Services Division 3