IBM eX5 Implementation Guide

Chapter 2. IBM eX5 technology 43

Figure 2-24 UEFI Power settings window

2.7.3 Performance-related individual system settings

The UEFI default settings are configured to provide optimal performance with reasonable

power consumption. Other operating modes are also available to meet various power and

performance requirements. However, individual system settings enable users to fine-tune the

desired characteristics of the IBM eX5 servers.

This section describes the UEFI settings that are related to system performance. Remember

that, in most cases, increasing system performance increases the power consumption of the

system.

Processors

Processor settings control the various performance and power features that are available on

the installed Xeon processor.

Figure 2-25 on page 44 shows the UEFI Processor system settings window with the default

values.

44 IBM eX5 Implementation Guide

Figure 2-25 UEFI Processor system settings panel

The following processor feature options are available:

򐂰 Turbo Mode (Default:

Enable)

This mode enables the processor to increase its clock speed dynamically as long as the

CPU does not exceed the

Thermal Design Power (TDP) for which it was designed. See

2.2.3, “Turbo Boost Technology” on page 18 for more information.

򐂰 Turbo Boost Power Optimization (Default:

Power Optimized)

This option specifies which algorithm to use when determining whether to overclock the

processor cores in Turbo Mode:

–

Power Optimized provides reasonable Turbo Mode in relation to power consumption.

Turbo Mode does not engage unless additional performance has been requested by

the operating system for a period of 2 seconds.

–

Traditional provides a more aggressive Turbo Mode operation.

Turbo Mode engages as more performance is requested by the operating system.

򐂰 Processor Performance States (Default:

Enable)

This option enables Intel Enhanced SpeedStep Technology that controls dynamic

processor frequency and voltage changes, depending on operation.

򐂰 CPU C-States (Default:

Enable)

This option enables dynamic processor frequency and voltage changes in the idle state,

providing potentially better power savings.

򐂰 C1 Enhanced Mode (Default:

Enable)

This option enables processor cores to enter an enhanced halt state to lower the voltage

requirement, and it provides better power savings.

Chapter 2. IBM eX5 technology 45

򐂰 Hyper-Threading (Default:

Enable)

This option enables logical multithreading in the processor, so that the operating system

can execute two threads simultaneously for each physical core.

򐂰 Execute Disable Bit (Default:

Enable)

This option enables the processor to disable the execution of certain memory areas,

therefore preventing buffer overflow attacks.

򐂰 Intel Virtualization Technology (Default:

Enable)

This option enables the processor hardware acceleration feature for virtualization.

򐂰 Processor Data Prefetch (Default:

Enable)

This option enables the memory data access prediction feature to be stored in the

processor cache.

򐂰 Cores in CPU Package (Default:

All)

This option sets the number of processor cores to be activated.

򐂰 QPI Link Frequency (Default:

Max Performance)

This option sets the operating frequency of the processor’s QPI link:

– Minimal Power provides less performance for better power savings.

The QPI link operates at the lowest frequency, which, in the eX5 systems, is 4.8 GT/s.

– Power Efficiency provides best performance per watt ratio.

The QPI link operates 1 step under the rated frequency, that is, 5.86 GT/s for

processors rated at 6.4 GT/s.

–

Max Performance provides the best system performance.

The QPI link operates at the rated frequency, that is, 6.4 GT/s for processors rated at

6.4 GT/s.

Memory

The Memory settings window provides the available memory operation options, as shown in

Figure 2-26 on page 46.

46 IBM eX5 Implementation Guide

Figure 2-26 UEFI Memory system settings panel

The following memory feature options are available:

򐂰 Memory Spare Mode (Default:

Disable)

This option enables memory sparing mode, as described in “Memory sparing” on page 29.

򐂰 Memory Mirror Mode (Default:

Non-Mirrored)

This option enables memory mirroring mode, as described in “Memory mirroring” on

page 28.

򐂰 Memory Speed (Default:

Max Performance)

This option sets the operating frequency of the installed DIMMs:

– Minimal Power provides less performance for better power savings.

The memory operates at the lowest supported frequency, which, in the eX5 systems, is

800 MHz.

– Power Efficiency provides the best performance per watt ratio.

The memory operates one step under the rated frequency, that is, 977 MHz for DIMMs

that are rated at 1066 MHz or higher.

–

Max Performance provides the best system performance.

The memory operates at the rated frequency, that is, 1066 MHz for DIMMs rated at

1066 MHz or higher.

Memory Mirror Mode: Memory Mirror Mode cannot be used in conjunction with

Memory Spare Mode.

Tip: Although memory DIMMs rated at 1333MHz are supported on eX5 servers, the

currently supported maximum memory operating frequency is 1066 MHz.