148 IBM System x3850 X6 and x3950 X6 Planning and Implementation Guide5.3.2 Processor settingsProcessor settings control the various performance and power features that are available onthe installed Xeon processor.Figure 5-16 shows the UEFI Processor system settings window with the default values.Figure 5-16 UEFI Processor system settings panelThe following processor feature options are available: Turbo Mode (Default: Enabled):This mode enables the processor to increase its clock speed dynamically as long as theCPU does not exceed the Thermal Design Power (TDP) for which it was designed. See“Turbo Boost Technology 2.0” on page 26, for additional information about Intel TurboBoost. Processor Performance States (Default: Enabled):This option enables Intel Enhanced SpeedStep Technology that controls dynamicprocessor frequency and voltage changes, depending on operation. CPU C-States (Default: Enabled):This option enables dynamic processor frequency and voltage changes in the idle state,providing potentially better power savings. Package ACPI C-State Limit (Default: ACPI C3):The Advanced Configuration and Power Interface (ACPI) is configured as ACPI C3 bydefault. C1 Enhanced Mode (Default: Enabled):This option enables processor cores to enter an enhanced halt state to lower the voltagerequirement, and it provides better power savings. Hyper-Threading (Default: Enabled):This option enables logical multithreading in the processor, so that the operating systemcan execute two threads simultaneously for each physical core. See “Hyper-ThreadingTechnology” on page 25 for more information. Execute Disable Bit (Default: Enabled):This option enables the processor to disable the execution of certain memory areas,therefore preventing buffer overflow attacks.
