SPEC CPU®2026 Flag Description
Lenovo Global Technology ThinkSystem SR665 V3 (2.10 GHz, AMD EPYC 9845)

Compilers: AMD Optimizing C/C++ Compiler Suite

Implicitly Included Flags

This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.

• • -O2
  • 

  • Moderate level of optimization which enables most optimizations. This is the default when no "-O" option is specified, or if no value is specified (i.e. "-O").

    If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.

  • Includes:
    • -O1
• • -O1
  • 

  • Somewhere between -O0 and -O2.

    If multiple "O" options are used, with or without level numbers, the last such option is the one that is effective.

Commands and Options Used to Submit Benchmark Runs

Using numactl to bind processes and memory to cores

For multi-copy runs or single copy runs on systems with multiple sockets, it is advantageous to bind a process to a particular core. Otherwise, the OS may arbitrarily move your process from one core to another. This can affect performance. To help, SPEC allows the use of a "submit" command where users can specify a utility to use to bind processes. We have found the utility 'numactl' to be the best choice.

numactl runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for a command and inherited by all of its children. The numactl flag "--physcpubind" specifies which core(s) to bind the process. "-l" instructs numactl to keep a process's memory on the local node while "-m" specifies which node(s) to place a process's memory. For full details on using numactl, please refer to your Linux documentation, 'man numactl'

Note that some older versions of numactl incorrectly interpret application arguments as its own. For example, with the command "numactl --physcpubind=0 -l a.out -m a", numactl will interpret a.out's "-m" option as its own "-m" option. To work around this problem, we put the command to be run in a shell script and then run the shell script using numactl. For example: "echo 'a.out -m a' > run.sh ; numactl --physcpubind=0 bash run.sh"

Shell, Environment, and Other Software Settings

numactl --interleave=all runcpu

numactl --interleave=all runcpu executes the SPEC CPU command runcpu so that memory is consumed across NUMA nodes rather than consumed from a single node. This helps prevent local node out-of-memory conditions which can occur when runcpu is executed without interleaving. For full details on using numactl, please refer to your Linux documentation, 'man numactl'

Transparent Huge Pages (THP)

THP is an abstraction layer that automates most aspects of creating, managing, and using huge pages. It is designed to hide much of the complexity in using huge pages from system administrators and developers. Huge pages increase the memory page size from 4 kilobytes to 2 megabytes. This provides significant performance advantages on systems with highly contended resources and large memory workloads. If memory utilization is too high or memory is badly fragmented which prevents huge pages being allocated, the kernel will assign smaller 4k pages instead. Most recent Linux OS releases have THP enabled by default.

THP usage is controlled by the sysfs setting /sys/kernel/mm/transparent_hugepage/enabled. Possible values:

• never: entirely disable THP usage.
• madvise: enable THP usage only inside regions marked MADV_HUGEPAGE using madvise(3).
• always: enable THP usage system-wide. This is the default.

The SPEC CPU benchmark codes themselves never explicitly request huge pages, as the mechanism to do that is OS-specific and can change over time. Libraries such as amdalloc which are used by the benchmarks may explicitly request huge pages, and use of such libraries can make the "madvise" setting relevant and useful.

When no huge pages are immediately available and one is requested, how the system handles the request for THP creation is controlled by the sysfs setting /sys/kernel/mm/transparent_hugepage/defrag. Possible values:

• never: if no THP are available to satisfy a request, do not attempt to make any.
• defer: an allocation requesting THP when none are available gets normal pages while requesting THP creation in the background.
• defer+madvise: acts like "always", but only for allocations in regions marked MADV_HUGEPAGE using madvise(3); for all other regions it's like "defer".
• madvise: acts like "always", but only for allocations in regions marked MADV_HUGEPAGE using madvise(3). This is the default.
• always: an allocation requesting THP when none are available will stall until some are made.

An application that "always" requests THP often can benefit from waiting for an allocation until those huge pages can be assembled.
For more information see the Linux transparent hugepage documentation.

ulimit -s <n>

Sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.

ulimit -l <n>

Sets the maximum size of memory that may be locked into physical memory.

powersave -f (on SuSE)

Makes the powersave daemon set the CPUs to the highest supported frequency.

/etc/init.d/cpuspeed stop (on Red Hat)

Disables the cpu frequency scaling program in order to set the CPUs to the highest supported frequency.

LD_LIBRARY_PATH

An environment variable that indicates the location in the filesystem of bundled libraries to use when running the benchmark binaries.

sysctl -w vm.dirty_ratio=8

Limits dirty cache to 8% of memory.

sysctl -w vm.swappiness=1

Limits swap usage to minimum necessary.

sysctl -w vm.zone_reclaim_mode=1

Frees local node memory first to avoid remote memory usage.

kernel/numa_balancing

This OS setting controls automatic NUMA balancing on memory mapping and process placement. NUMA balancing incurs overhead for no benefit on workloads that are already bound to NUMA nodes.

Possible settings:

• 0: disables this feature
• 1: enables the feature (this is the default)

For more information see the numa_balancing entry in the Linux sysctl documentation.

kernel/randomize_va_space (ASLR)

This setting can be used to select the type of process address space randomization. Defaults differ based on whether the architecture supports ASLR, whether the kernel was built with the CONFIG_COMPAT_BRK option or not, or the kernel boot options used.

Possible settings:

• 0 - Turn the process address space randomization off. This is the default for architectures that do not support this feature anyway, and kernels that are booted with the "norandmaps" parameter.
• 1 - Randomize addresses of mmap base, stack, and VDSO pages. This is the default if the CONFIG_COMPAT_BRK option is enabled at kernel build time.
• 2 - Additionally enable heap randomization. This is the default if CONFIG_COMPAT_BRK is disabled.

Disabling ASLR can make process execution more deterministic and runtimes more consistent. For more information see the randomize_va_space entry in the Linux sysctl documentation.

vm/drop_caches

The two commands are equivalent: echo 3> /proc/sys/vm/drop_caches and sysctl -w vm.drop_caches=3 Both must be run as root. The commands are used to free up the filesystem page cache, dentries, and inodes.

Possible settings:

• 1 - Clear pagecache
• 2 - Clear dentries and inodes
• 3 - Clear pagecache, dentries, and inodes

MALLOC_CONF

The amdalloc library is a variant of jemalloc library. The amdalloc library has tunable parameters, many of which may be changed at run-time via several mechanisms, one of which is the MALLOC_CONF environment variable. Other methods, as well as the order in which they're referenced, are detailed in the jemalloc documentation's TUNING section.

The options that can be tuned at run-time are everything in the jemalloc documentation's MALLCTL NAMESPACE section that begins with "opt.".

The options that may be encountered in SPEC CPU 2017 results are detailed here:

• retain:true - Causes unused virtual memory to be retained for later reuse rather than discarding it. This is the default for 64-bit Linux.
• thp:never - Attempts to never utilize huge pages by using MADV_NOHUGEPAGE on all mappings. This option has no effect except when THP is set to "madvise".

PGHPF_ZMEM

An environment variable used to initialize the allocated memory. Setting PGHPF_ZMEM to "Yes" has the effect of initializing all allocated memory to zero.

GOMP_CPU_AFFINITY

This environment variable is used to set the thread affinity for threads spawned by OpenMP.

OMP_DYNAMIC

This environment variable is defined as part of the OpenMP standard. Setting it to "false" prevents the OpenMP runtime from dynamically adjusting the number of threads to use for parallel execution.

For more information, see chapter 4 ("Environment Variables") in the OpenMP 4.5 Specification.

OMP_SCHEDULE

This environment variable is defined as part of the OpenMP standard. Setting it to "static" causes loop iterations to be assigned to threads in round-robin fashion in the order of the thread number.

For more information, see chapter 4 ("Environment Variables") in the OpenMP 4.5 Specification.

OMP_STACKSIZE

This environment variable is defined as part of the OpenMP standard and controls the size of the stack for threads created by OpenMP.

For more information, see chapter 4 ("Environment Variables") in the OpenMP 4.5 Specification.

OMP_THREAD_LIMIT

This environment variable is defined as part of the OpenMP standard and limits the maximum number of OpenMP threads that can be created.

For more information, see chapter 4 ("Environment Variables") in the OpenMP 4.5 Specification.

Operating System Tuning Parameters

sched_cfs_bandwidth_slice_us

This OS setting controls the amount of run-time(bandwidth) transferred to a run queue from the task's control group bandwidth pool. Small values allow the global bandwidth to be shared in a fine-grained manner among tasks, larger values reduce transfer overhead. The default value is 5000 (ns).

sched_latency_ns

This OS setting configures targeted preemption latency for CPU bound tasks. The default value is 24000000 (ns).

sched_migration_cost_ns

Amount of time after the last execution that a task is considered to be "cache hot" in migration decisions. A "hot" task is less likely to be migrated to another CPU, so increasing this variable reduces task migrations. The default value is 500000 (ns).

sched_min_granularity_ns

This OS setting controls the minimal preemption granularity for CPU bound tasks. As the number of runnable tasks increases, CFS(Complete Fair Scheduler), the scheduler of the Linux kernel, decreases the timeslices of tasks. If the number of runnable tasks exceeds sched_latency_ns/sched_min_granularity_ns, the timeslice becomes number_of_running_tasks * sched_min_granularity_ns. The default value is 8000000 (ns).

sched_wakeup_granularity_ns

This OS setting controls the wake-up preemption granularity. Increasing this variable reduces wake-up preemption, reducing disturbance of compute bound tasks. Lowering it improves wake-up latency and throughput for latency critical tasks, particularly when a short duty cycle load component must compete with CPU bound components. The default value is 10000000 (ns).

numa_balancing

This OS setting controls automatic NUMA balancing on memory mapping and process placement. NUMA balancing incurs overhead for no benefit on workloads that are already bound to NUMA nodes. Possible settings:

• 0: disables this feature
• 1: enables the feature (this is the default)

For more information see the numa_balancing entry in the Linux sysctl documentation.

kernel.randomize_va_space (ASLR)

This setting can be used to select the type of process address space randomization. Defaults differ based on whether the architecture supports ASLR, whether the kernel was built with the CONFIG_COMPAT_BRK option or not, or the kernel boot options used.
Possible settings:

• 0: Turn process address space randomization off.
• 1: Randomize addresses of mmap base, stack, and VDSO pages.
• 2: Additionally randomize the heap. (This is probably the default.)

Disabling ASLR can make process execution more deterministic and runtimes more consistent. For more information see the randomize_va_space entry in the Linux sysctl documentation.

Transparent Hugepages (THP)

THP is an abstraction layer that automates most aspects of creating, managing, and using huge pages. It is designed to hide much of the complexity in using huge pages from system administrators and developers. Huge pages increase the memory page size from 4 kilobytes to 2 megabytes. This provides significant performance advantages on systems with highly contended resources and large memory workloads. If memory utilization is too high or memory is badly fragmented which prevents hugepages being allocated, the kernel will assign smaller 4k pages instead. Most recent Linux OS releases have THP enabled by default.
THP usage is controlled by the sysfs setting /sys/kernel/mm/transparent_hugepage/enabled. Possible values:

• never: entirely disable THP usage.
• madvise: enable THP usage only inside regions marked MADV_HUGEPAGE using madvise(3).
• always: enable THP usage system-wide. This is the default.

THP creation is controlled by the sysfs setting /sys/kernel/mm/transparent_hugepage/defrag. Possible values:

• never: if no THP are available to satisfy a request, do not attempt to make any.
• defer: an allocation requesting THP when none are available get normal pages while requesting THP creation in the background.
• defer+madvise: acts like "always", but only for allocations in regions marked MADV_HUGEPAGE using madvise(3); for all other regions it's like "defer".
• madvise: acts like "always", but only for allocations in regions marked MADV_HUGEPAGE using madvise(3). This is the default.
• always: an allocation requesting THP when none are available will stall until some are made.

An application that "always" requests THP often can benefit from waiting for an allocation until those huge pages can be assembled.
For more information see the Linux transparent hugepage documentation.

tuned-adm

The tuned-adm tool is a commandline interface for switching between different tuning profiles available to the tuned tuning daemon available in supported Linux distros. The default configuration file is located in /etc/tuned.conf and the supported profiles can be found in /etc/tune-profiles. Some profiles that may be available by default include: balanced, powersave, laptop-ac-powersave, laptop-battery-powersave, spindown-disk, throughput-performance, latency-performance, enterprise-storage, virtual-host. To set a profile, one can issue the command "tuned-adm profile (profile_name)". Here are details about relevant profiles:

• throughput-performance: Server profile for typical throughput tuning. This profile disables tuned and ktune power saving features, enables sysctl settings that may improve disk and network IO throughput performance, switches to the deadline scheduler, and sets the CPU governor to performance.
• latency-performance: Server profile for typical latency tuning. This profile disables tuned and ktune power saving features, enables the deadline IO scheduler, and sets the CPU governor to performance.
• enterprise-storage: Server profile for high disk throughput tuning. This profile disables tuned and ktune power saving features, enables the deadline IO scheduler, enables hugepages and disables disk barriers, increases disk readahead values, and sets the CPU governor to performance.
• balanced: Server profile for balance power saving and performance tuning. This profile enables CPU and disk plugins of tuned and makes the conservative governor is active and also set the CPU energy performance bias to normal. It also enables power saving on audio and graphics card.
• powesave: Server profile for Maximal power saving tuning for whole system. This profile set the CPU governor to ondemand governor and energy performance bias to powersave. It also enable powersave on USB, SATA, audio and grahic card.
• virtual-host: Profile optimized for virtual hosts based on throughput-performance profile. This profile additionally enabled more aggresive writeback for dirty pages.

dirty_background_ratio

Set through "echo 40 > /proc/sys/vm/dirty_background_ratio". This setting can help Linux disk caching and performance by setting the percentage of system memory that can be filled with dirty pages.

dirty_ratio

Set through "echo 8 > /proc/sys/vm/dirty_ratio". This setting is the absolute maximum amount of system memory that can be filled with dirty pages before everything must get committed to disk.

ksm/sleep_millisecs

Set through "echo 200 > /sys/kernel/mm/ksm/sleep_millisecs". This setting controls how many milliseconds the ksmd (KSM daemon) should sleep before the next scan.

swappiness

The swappiness value can range from 1 to 100. A value of 100 will cause the kernel to swap out inactive processes frequently in favor of file system performance, resulting in large disk cache sizes. A value of 1 tells the kernel to only swap processes to disk if absolutely necessary. This can be set through a command like "echo 1 > /proc/sys/vm/swappiness"

Zone Reclaim Mode

Zone reclaim allows the reclaiming of pages from a zone if the number of free pages falls below a watermark even if other zones still have enough pages available. Reclaiming a page can be more beneficial than taking the performance penalties that are associated with allocating a page on a remote zone, especially for NUMA machines. To tell the kernel to free local node memory rather than grabbing free memory from remote nodes, use a command like "echo 1 > /proc/sys/vm/zone_reclaim_mode"

Free the file system page cache

The command "echo 3> /proc/sys/vm/drop_caches" is used to free pagecache, dentries and inodes.

cpupower

The OS 'cpupower' utility is used to change CPU power governors settings. Available settings are:

• performance: Run the CPU at the maximum frequency.
• powersave: Run the CPU at the minimum frequency.
• ondemand: Scales the frequency dynamically according to current load. Jumps to the highest frequency and then possibly back off as the idle time increases.

Firmware / BIOS / Microcode Settings

Choose Operating Mode: (Default="Maximum Efficiency")

Select the operating mode based on your preference. Note, power savings and performance are also highly dependent on hardware and software running on system.

• "Maximum Efficiency" 'Efficiency' balances performance and power consumption.
• "Maximum Performance"'Performance' maxmizes performance minimizes latency with little regard to power consumption.
• "Custom Mode" When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose Custom Mode. Custom Mode will inherit the UEFI settings from the previous preset operating mode. For example, if the previous operating mode was the Maximum Performance operating mode and then Custom Mode was selected, all the settings from the Maximum Performance operating mode will be inherited.

Determinism Slider:

• "Performance (default)" When set to Performance, performance is more predictable (deterministic) and operates at the lowest common denominator among the cores. But aggregate peak performance may be reduced. Aggregate performance may be higher, but predictability is lower.
• "Power" When set to Power, cores can scale frequency independently.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

Core Performance Boost:

Allows the processor to opportunistically increase a set of CPU cores higher than the CPU’s rated base clock speed, based on the number of active cores, power and thermal headroom in a system.

• "Enabled (default)" When set to Enable, cores can go to turbo frequencies.
• "Disabled" Disables Core Performance Boost so the processor cannot opportunistically increase a set of CPU cores higher than the CPU’s rated base clock speed.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

Global C-state Control:

C-states are idle power saving states. This setting enables and disables C-states on the server across all cores. When disabled, the CPU cores can only be in C0 (active) or C1 state. C1 state can never be disabled. A CPU core will be in the C1 state if the core is halted by the operating system.

• "Disabled" I/O based C-state generation and Data Fabric (DF) C-states are disabled.
• "Enabled (default)" I/O based C-state generation and DF C-states are enabled.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

cTDP:

Sets the maximum power consumption for CPU. cTDP is only configurable before OS boot.

• "Auto" Sets cTDP=TDP for the installed CPU SKU.
• "Maximum" Maximum sets the maximum allowed cTDP value for the installed CPU SKU.
• "Manual" Usually, maximum is greater than TDP. If a manual value is entered that is larger than the max value allowed, the value will be internally limited to the maximum allowable value.

Default is Auto. When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

cTDP Manual:

cTDP is the acronym for Configurable TDP. Some Rome CPU skus support a default TDP and a higher cTDP expressed in Watts.

Model	Normal TDP	Minimum TDP	Maximum TDP
EPYC 9755	500	450	500
EPYC 9655	400	320	400
EPYC 9655P	400	320	400
EPYC 9565	400	320	400
EPYC 9575F	400	320	400
EPYC 9555	360	320	400
EPYC 9555P	360	320	400
EPYC 9535	300	240	300
EPYC 9475F	400	320	400
EPYC 9455	300	240	300
EPYC 9455P	300	240	300
EPYC 9365	300	240	300
EPYC 9375F	320	320	400
EPYC 9355	280	240	300
EPYC 9355P	280	240	300
EPYC 9335	210	200	240
EPYC 9275F	320	320	400
EPYC 9255	200	200	240
EPYC 9175F	320	320	400
EPYC 9135	200	200	240
EPYC 9115	125	120	155
EPYC 9015	125	120	155
EPYC 9965	500	450	500
EPYC 9845	390	320	400
EPYC 9825	390	320	400
EPYC 9745	400	320	400
EPYC 9645	320	320	400
EPYC 9654	360	320	400
EPYC 9654P	360	320	400
EPYC 9634	290	240	300
EPYC 9554	360	320	400
EPYC 9554P	360	320	400
EPYC 9534	280	240	300
EPYC 9474F	360	320	400
EPYC 9454	290	240	300
EPYC 9454P	290	240	300
EPYC 9374F	320	320	400
EPYC 9354	280	240	300
EPYC 9354P	280	240	300
EPYC 9334	210	200	240
EPYC 9274F	320	320	400
EPYC 9254	200	200	240
EPYC 9224	200	200	240
EPYC 9174F	320	320	400
EPYC 9124	200	200	240
EPYC 9754	360	320	400
EPYC 9734	340	320	400
EPYC 7663P	240	225	240
EPYC 7643P	225	225	240
EPYC 7303P	130	120	150
EPYC 7303	130	120	150
EPYC 7203P	120	120	150
EPYC 7203	120	120	150
EPYC 9684X	400	320	400

Default is 0. When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

Memory Speed:

Select the desired memory speed. Faster speeds offer better performance but consume more power. Default is Maximum. When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

4-Link xGMI Max Speed:

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.

• "Minimal(default)"Minimal will result in the xGMI speed getting set to the minimal value, the minimal xGMI max speed is 16GT/s
• "18Gbps" 2 speed bin down from the maximum speed.
• "25Gbps" 1 speed bin down from the maximum speed.
• "32Gbps"Maximum xGMI link speed.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

NUMA Nodes per Socket:

Specifies the number of desired NUMA nodes per socket.

• "NPS0"NPS0 will attempt to interleave the 2 CPU sockets together.
• "NPS1"NPS1 sets one NUMA node per socket.
• "NPS2"NPS2 sets two NUMA nodes per socket, one per Left/Right Half of the SoC.
• "NPS4"NPS4 sets four NUMA nodes per socket, one per Quadrant.

Default is NPS1.

Package Power Limit:

This Parameter sets the CPU package power limit. The maximum value allowed for PPL is the cTDP limit.

• "Auto(default)"Set to maximum value allowed by installed CPU.
• "Manual"Let the user set a power limit and exposes Package Power Limit value applicable for all poplulated processors in the system. If a manual value entered that is larger than the maximum value allowed(cTDP Maximum), the value will be internally limited to maximum allowable value.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

SMT Mode:

Can be used to disable symmetric multithreading. To re-enable SMT, a POWER CYCLE is needed after selecting Enable.

• "Enabled (default)"Enables simultaneous multithreading.
• "Disabled"Disables simultaneous multithreading so that only one thread or CPU instruction stream is run on a physical CPU core

ACPI SRAT L3 Cache as NUMA Domain:

When enabled, the last level cache in each CCX in the system will be declared as a separate NUMA domain. It can improve performance for highly NUMA optimized workloads if workloads or components of workloads can be pinned to cores in a CCX and if they can benefit from sharing an L3 cache.

• "Disabled (default)"When disabled, NUMA domains will be identified according to the NUMA Nodes per Socket parameter setting.
• "Enabled"When enabled, each Core Complex (CCX) in the system will become a separate NUMA domain.

DF P-states:

DF P-states is the processor uncore P-states. Setting DF P-states to P0, P1, forces the uncore to operate in a specific P-state frequency.

• "Auto(default)"When Auto is Selected, the CPU DF P-states (uncore P-states) will be dynamically adjusted. That is, their frequency will dynamically change based on the workload.
• "P0"Highest-performing Infinity Fabric P-state.
• "P1"Second-highest-performing Infinity Fabric P-state.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

L1 Stream HW Prefetcher:

Fetches the next cache line int to the L1 cache when cached lines are reused within a certain time period or accessed sequentially.

• "Enabled(default)"Enable L1 Stream HW Prefetcher.
• "Disabled"Disable L1 Stream HW Prefetcher.

L1 Stride Prefetcher:

Uses memory access history to fetch additional data lines into L1 cache when each access is a constant distance from previous.

• "Enabled(default)"Enable L1 Stride Prefetcher.
• "Disabled"Disable L1 Stride Prefetcher.

L2 Stream HW Prefetcher:

Fetches the next cache line int to the L2 cache when cached lines are reused within a certain time period or accessed sequentially.

• "Enabled(default)"Enable L2 Stream HW Prefetcher.
• "Disabled"Disable L2 Stream HW Prefetcher.

L1 Region Prefetcher:

Enabled/Disabled L1 Region Prefetcher. Fetches 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 workload may benefit from having it disabled. Default is Enabled

BoostFmax:

This value specifies the maximum boost frequency limit to apply to all cores. If the BoostFmax is set to something higher than the boost algorithms allow, the SoC will not go beyond the allowable frequency that the algorithms support.

• "Auto(default)"Auto set the boost frequency to the fused value for the installed CPU.
• "Manual"A 4 digit number representing the maximum boost frequency in MHz.

BoostFmax Manual:

Select the values to specifies the maximum boost frequency limit to apply to all cores. Default is 0.

Power Profile Selection:

This setting specifies power profile

• "Efficiency Mode(default)"Maximum frequecy per watt by opportunistically reducing frequency/power.
• "High-Performance Mode"Favor core performance more than IO die performance.
• "Maximum IO Performance Mode"Favor IO die performance more than core performance.
• "Balanced Memory Performance Mode"Biases the memory subsystem and Infinity Fabric performance towards efficiency, lowering the frequency of fabric and the width of the xGMI links under a light workload.
• "Balanced Core Performance Mode"Biases towards consistent core performance across varying core utilization levels by preventing active cores from using the power budget of inactive cores.
• "Balanced Core Memory Performance Mode"Combines the Balanced Memory Performance and the Balanced Core Performance Mode.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

P-State:

This setting enables or disables CPU's P-State.

• "Enabled(default)"Core frequency can move between SKU-specific predefined P-States based on its utilization to balance performance and power usage.
• "Disabled"Sets the core frequency to the highest-available frequency within P0.

When a preset mode is selected, the low-level settings are not changeable and will be grayed out. If user would like to change the settings, please choose [Custom Mode] in "Operating Mode" located under "System Setting" submenu.

xGMI Maximum Link Width:

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

• "Auto(default)"use the default xGMI link width controller settings, sets the maximum width based on the system capabilities, the max xGMI link width default is set to x16.
• "0"Specify a custom xGMI link with controller setting, set max xGMI link width to x8.
• "1"Specify a custom xGMI link with controller setting, set max xGMI link width to x16.

DRAM Scrub Time:

Memory reliability parameter that sets the period of time between successive DRAM scrub events. Performance may be reduced with more frequent DRAM scrub events. Possible values:

• "Disable"
• "1 hour"
• "4 hour"
• "8 hour"
• "16 hour"
• "24 hour (default)"
• "48 hour"

Memory Interleave:

This setting allows interleaved memory accesses across multiple memory channels in each socket, providing higher memory bandwidth.

• "Enabled(default)"Interleaving is automatically enabled if memory DIMM configuration supports it.
• "Disabled"No interleaving.

GMI Folding:

GMI stands for Global Memory Interconnect. It's an AMD Infinity fabric interface that offers data communication between the CPU die and the I/O die. GMI Folding reduces the number of active communication lanes on the inifinity fabric in specific scenarios, effectively "folding" the lanes.

• "Enabled(default)"Enable GMI Folding feature to save link power.
• "Disabled"Disable GMI Folding feature to decrease memory latency.

Periodic Directory Rinse (PDR) Tuning:

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

• "Memory-Sensitive"May accelerate high b/w scenarios.
• "Cache-Bound"May allelerate cache-bound secenarios.
• "Neutral"Fallback option for unknown or mixed scenarios.
• "Adaptive"Adjusts based on Memory/Cache Activity.
• "Auto"Will use silicon reset value.

Default is Auto.

Fan Speed Boost:

This setting allows additional cooling to the server based on ambient temperature. It can increase the fan over normal speed by controlled thermal algorithm. There will be no change if fan already running at full speed.

• "Normal"No fan speed boost.
• "Low"Slight boost in fan speed.
• "Medium"Moderate boost in fan speed.
• "High"Large boost in fan speed.

Default is Normal.

C State Support:

Select whether to enable or disable the CPU power management state to minimize idle power consumption of the processor.

• "Enabled"The operating system initiates the C-state transitions.
• "Disabled"Only C0 and C1 are used by the OS. C1 gets enabled automatically when an OS autohalts.

Default is Enabled.

AMD Secure Virtual Machine:

Select whether to enabled or disabled AMD Virtuailiztion technology. When set to Enabled, the BIOS will enable processor Virtualization features and provide the virtualization support to the Operating System (OS) through the DMAR table. Default is Enabled.

CPB Mode:

Allows the processor to dynamically control and adjust its operating frequency to increase performance when needed and maintain lower power and thermal characteristics during normal operation.

• "Enabled"When set to Enable, cores can go to turbo frequencies.
• "Disabled"Disables Core Performance Boost so the processor cannot opportunistically increase a set of CPU cores higher than the CPU’s rated base clock speed.

Default is Enabled.

Flag description origin markings:

	Indicates that the flag description came from the user flags file.
	Indicates that the flag description came from the suite-wide flags file.
	Indicates that the flag description came from a per-benchmark flags file.

For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact info@spec.org
Copyright 2026 Standard Performance Evaluation Corporation
Tested with SPEC CPU®2026 v0.902.0.
Report generated on 2026-05-11 16:38:02 by SPEC CPU®2026 flags formatter (5b352a85).