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Processors

This menu offers options to change the processor settings.

Table 1. Processors
ItemOptionsDescription
Determinism Slider
  • Power

  • Performance (Default)

When [Performance] is selected, performance is more predictable (deterministic) and operates at the lowest common denominator among the cores. But aggregate peak performance may be reduced.

When [Power] is selected, cores can scale frequency independently. Aggregate performance may be higher, but predictability is lower.

Core Performance Boost
  • Disabled

  • Enabled (Default)

When [Enabled] is selected, cores can run at turbo frequencies.

cTDP
  • Maximum

  • Manual

  • Auto (Default)

Set the maximum power consumption for the processor.

[Auto] sets cTDP=TDP for the installed processor SKU.

[Maximum] sets the maximum allowed cTDP value for the installed processor SKU. Usually, maximum is greater than TDP. If a manual value is entered that is greater than the maximum value allowed, the value will be internally limited to the maximum allowable value. cTDP is only configurable before booting the operating system.

cTDP Manual

[0]

Set the power consumption for the processor.

Note
This feature appears only when cTDP is set to [Manual].
Package Power Limit
  • Maximum

  • Manual

  • Auto (Default)

Set the CPU package power limit.

If [Auto] is selected, it will be set to the maximum value allowed by the installed processor.

If a manual value is entered that is greater than the maximum value allowed, the value will be internally limited to the maximum allowable value.

The maximum value allowed for PPL is the cTDP limit. Compared to cTDP, Package Power Limit (PPL) can be changed at runtime and PPL supports a much lower effective limit than cTDP.

Package Power Limit Manual

[0]

Package Power Limit (PPT) [W].

4-Link xGMI Max Speed
Note
Only available on SD665 V3 servers.
  • Minimum(Default)

  • 25Gbps

  • 32Gbps

Sets the xGMI speed.

N is the maximum speed and is auto-calculated from the system board capabilities. For system boards that do not support 4 discrete xGMI speed choices, some menu choices besides “Minimum” will result in the xGMI speed getting set to the minimum value.

3-Link xGMI Max Speed
Note
Only available on SR675 V3 servers.
  • Minimum(Default)

  • 25Gbps

  • 32Gbps

Sets the xGMI speed.

N is the maximum speed and is auto-calculated from the system board capabilities. NUMA-unaware workloads may need maximum xGMI bandwidth because of extensive cross socket communications. NUMA-aware workloads may want to minimize xGMI power because they do not have a lot of cross socket traffic and prefer to use the increased CPU boost.

Global C-state Control
  • Disabled

  • Enabled (Default)

Enable or disable IO based C-state generation and DF C-states.

DF P-states
  • Auto (Default)

  • P0

  • P1

  • P2

  • P3

  • P4

When [Auto] is selected, the processor DF P-states (uncore P-states) are dynamically adjusted. The frequency dynamically changes based on the workload.

Selecting P0, P1, P2, P3 or P4 forces the DF to a specific P-state frequency.

DF C-States
  • Disabled

  • Enabled (Default)

Enable or disable data fabric (DF) C-states.

Data fabric C-states may be entered when all cores are in CC6.

MONITOR/MWAIT
Note
This item is not available on servers with the 5th Gen AMD EPYC processors (9005 series).
  • Enabled (Default)

  • Disabled

MONITOR/MWAIT instructions are used to engage C-states. Some operating systems re-enable C-states even when they are disabled in setup. To prevent this, do the following:
  1. Disable MONNITOR/MWAIT.

  2. Choose System Settings > Operating Modes > Choose Operating Mode > Custom Mode. and choose System Settings > DF C-States > Disabled
P-State
  • Enabled (Default)

  • Disabled

  • [Enabled]: Core frequency can move between SKU-specific predefined P-States based on its utilization to balance performance and power usage.

  • [Disabled]: Set the core frequency to the highest-available frequency within P0.

ACPI SRAT L3 Cache as NUMA Domain
  • Enabled

  • Disabled (Default)

If [Enabled] is selected, each CCX in the system will be declared as a separate NUMA domain.

If [Disabled] is selected, memory addressing/NUMA nodes per socket will be declared.

L1 Stream HW Prefetcher
  • Enabled (Default)

  • Disabled

Enable or disable L1 stream HW prefetcher.

Fetch the next cache line into the L1 cache when cached lines are reused within a certain time period or accessed sequentially.

L2 Stream HW Prefetcher
  • Enabled (Default)

  • Disabled

Enable or disable L2 Stream HW Prefetcher.

Fetch the next cache line into the L2 cache when cached lines are reused within a certain time period or accessed sequentially.

L1 Stride Prefetcher
  • Disabled

  • Enabled (Default)

Enable or disable L1 Stride Prefetcher.

Use memory access history to fetch additional data lines into L1 cache when each access is at a constant distance from the previous one. Some workloads may benefit when this feature is set to [Disabled].

L1 Region Prefetcher
  • Disabled

  • Enabled (Default)

Enable or disable L1 Region Prefetcher.

Fetch additional data lines into L1 cache when the data access for a given instruction tends to be followed by a consistent pattern of subsequent accesses. Some workloads may benefit when this feature is set to [Disabled].

L2 Up/Down Prefetcher
  • Disabled

  • Enabled (Default)

Enable or disable L2 Up/Down Prefetcher.

Use memory access history to determine to fetch the next or previous line for all memory accesses. Some workloads may benefit when this feature is set to [Disabled].

SMT Mode
  • Enabled (Default)

  • Disabled

This feature can be used to disable symmetric multithreading. To re-enable SMT, a power cycle is needed after selecting [Enabled].

CPPC
  • Enabled (Default)

  • Disabled

CPPC (cooperative processor performance control) is a way for the operating system to affect the performance of a processor on a contiguous and abstract scale without knowledge of power budgets or discrete processor frequencies.

Note
The CPPC option will be grayed out if P-State sets to [Disable].
BoostFmax
  • Auto (Default)

  • Manual

Maximum boost frequency.

[Auto] sets the boost frequency to the fused value for the installed processor.

When a manual value is entered, the value entered is a 4 digit number representing the maximum boost frequency in MHz. The value entered applies to all cores.

BoostFmax Manual

[0]

Maximum boost frequency.

Note
This feature is available only when BoostFmax is set to [Manual].
SVM Mode
  • Disabled

  • Enabled (Default)

Enable or disable processor Virtualization.

xGMI Maximum Link Width

Note
Available on 2-socket platforms only.
  • x4

  • x8

  • x16

  • Auto (Default)

Sets the xGMI maximum allowable link width. The actual xGMI link width can vary between the minimum and maximum width selected.

[Auto]: Set the maximum xGMI link width based on the system capabilities.

APIC Mode
  • xAPIC

  • x2APIC

  • Auto (Default)

[xAPIC] scales to only 255 hardware threads.

[x2APIC] scales beyond 255 hardware threads but not supported by some legacy OS versions.

[Auto] uses [x2APIC] only if 256 hardware threads are in the system. Otherwise, use [xAPIC].

Note
[x2APIC] option will be grayed out if IOMMU is set as [Disabled].
SEV-SNP Support
  • Enabled

  • Disabled (Default)

Enable the support for Secure Encrypted Virtualization and Secure Nested Paging.

HSMP Support
  • Disabled

  • Enabled

  • Auto(Default)

HSMP (Host System Management Port) is an interface to provide OS-level software with access to system management functions via a set of mailbox registers

  • [Auto]: Use hardware default value.

  • [Enabled]: Enable HSMP interface support.

  • [Disabled]: Disable HSMP interface support.

Enhanced REP MOVSB/STOSB
  • Disabled

  • Enabled

    (Default)

(ERSM) Can be disabled for analysis purposes as long as OS supports it.

Note
This item is for VMware OS.
Fast Short REP MOVSB
  • Disabled

  • Enabled(Default)

(FSRM) Can be disabled for analysis purposes as long as OS supports it.

Note
This item is for VMware OS. Linux OS doesn’t support enabling FSRM alone.
SNP Memory (RMP Table) Coverage
  • Disabled(Default)

  • Enabled

  • Custom

[Enabled] means that the ENTIRE system memory is covered.

Note
For servers with the 5th Gen AMD EPYC processors (9005 series), this item is only visible when SMEE is set to [Enable] and SEV Control is set to [Enable].
Amount of Memory to Cover2000Specify MB of System Memory to be covered in Hex.
Note
This item is only available when SNP Memory (RMP Table) Coverage is set to [Custom].
Split RMP Table
  • Disabled(Default)

  • Enabled

Control RMP Table Allocation.
  • [Enabled]: Split RMP Table across sockets.

  • [Disabled]: Allocate RMP Table at the end of memory.

Note
  • For servers with the 4th Gen AMD EPYC processors (9004 series), this item is only available when SNP Memory (RMP Table) Coverage is set to [Custom].

  • For servers with the 5th Gen AMD EPYC processors (9005 series), this item is only visible when SMEE is set to [Enable], SEV Control is set to [Enable] and SNP Memory (RMP Table) Coverage is set to [Custom] or [Enabled].

3D V-Cache

  • Auto

  • Disabled

    Note
    [Disabled] is only for servers with the 5th Gen AMD EPYC processors (9005 series)

3D V-Cache only takes effect in systems powered by AMD EPYC Processors equipped with AMD 3D V-Cache technology. Lenovo recommends setting this option to [Auto] to leverage the extra cache.

ACPI CST C2 Latency

  • 800 (for servers with the 4th Gen AMD EPYC processors (9004 series)

  • 100 (for servers with the 5th Gen AMD EPYC processors (9005 series)

Enter in microseconds (decimal value).

Larger C2 latency values will reduce the number of C2 transitions and reduce C2 residency. Fewer transitions can help when performance is sensitive to the latency of C2 entry and exit. Higher residency can improve performance by allowing higher frequency boost and reduce idle power. The best value will be dependent on kernel version, use case, and workload.

xGMI P-States

  • Auto(Default)

  • P0

  • P1

  • When [Auto] is selected, the xGMI P-State will be dynamically adjusted and it will change the xGMI link speed based on the workload.

  • Select [P0] to target High xGMI Link Speed and select [P1] to target Low xGMI Link Speed.

Note
This item is only available on servers with the 5th Gen AMD EPYC processors (9005 series).

Probe Filter Organization

  • Dedicated (for servers with the 4th Gen AMD EPYC processors (9004 series))

  • Shared (for servers with the 5th Gen AMD EPYC processors (9005 series))

Specify whether multiple memory/CXL channels will share probe filter storage. For memory sizes of 16TB or larger, this feature is ignored as it is auto-selected to [Shared].

Periodic Directory Rinse (PDR) Tuning (for servers with the 4th Gen AMD EPYC processors (9004 series))

  • Memory-Sensitive

  • Cache-Bound

  • Neutral

  • Adaptive

  • Auto(Default)

Control PDR settings that may impact performance by workload and/or processor.

  • [Memory-Sensitive]: May accelerate high b/w scenarios.

  • [Cache-Bound]: May accelerate cache-bound scenarios.

  • [Neutral]: Fallback option for unknown or mixed scenarios.

  • [Adaptive]: Adjust based on Memory/Cache Activity.

  • [Auto]: Will use silicon reset value.

Periodic Directory Rinse (PDR) Tuning (for servers with the 5th Gen AMD EPYC processors (9005 series))
  • Periodic

  • Blended(Default)

Controls PDR settings that may impact performance by workload and/or processor.

[Blended] (Cache Load Based Floss with Background RefClock Based Floss): Demand based Directory Rinse; rinse frequency dynamically changes based on workload demand.

[Periodic] (RefClock Based Floss Only): Rate based Directory Rinse; rinse frequency is fixed.

Split RMP Table

All (Default)

List of all available core counts based on CCDs and Cores Per CCD.

Select total number of enabled CPU cores per socket to be activated. Available options are dependent on processor SKU topology.

Note
  • Reducing the number of processor cores activated can adversely affect the performance.

  • n is the maximum number of cores that installed processor supports. For example, it will show [All], [1], [2], [3], [4], [5] if the installed processor supports 6 cores.

Secured-Core

N/A

Secured-Core configuration setup page.

Processor Details

N/A

Display summary of the installed processors.