SPEC CPU2006 Platform Settings for Intel-based systems

Firmware / BIOS / Microcode Settings

Hardware Prefetch:

This BIOS option allows the enabling/disabling of a processor mechanism to prefetch data into the cache according to a pattern-recognition algorithm In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Adjacent Sector Prefetch:

This BIOS option allows the enabling/disabling of a processor mechanism to fetch the adjacent cache line within a 128-byte sector that contains the data needed due to a cache line miss. In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

Hyper-Threading:

This BIOS option allows the enabling/disabling of Intel's Hyper-Threading (HT) Technology. HT Technology allows multithreaded software applications execute two threads in parallel within each processor core.

DIMM Voltage:

Specify the operating voltage of memory. The memory voltage may differ from that specified in this parameter depending on memory configuration.

Performance Profile:

This BIOS switch allows 3 options: "Custom", "Max Performance", and "Energy Efficiency". The default is "Custom".

• "Max Performance" sets all CPU power efficiency automatically to get the Max Performance,with this option, CPU power management configuration can't be set manually.

• "Energy Efficiency" sets the CPU power efficiency automatically, with this option, CPU power management configurations can't be set manually.

• "Custom" allows the enabled/disabled of "Enhanced Intel SpeedStep Technology", "Turbo Mode", "C1E Support", "Core C3", "Core C6", "CPU Performance and Energy Bias", this option also allows set "Thermal Profile" to "Max Performance", "Energy Efficiency" or "High Fan Speed", and set Memory Power Savings to "Auto" or "Disabled".The initial defaults in Custom mode are:

Turbo Mode:

Intel Turbo Boost Technology allows processor cores to run faster than the rated operating frequency if they are operating below power, current, and temperature specification limits. Disabling this feature will reduce power usage but will reduce the system's maximum achievable performance under some workloads.

C States:

Enabling the CPU States causes the CPU to enter a low-power mode when the CPU is idle.

Package C State Limit:

Specifies the lowest C-state for the processor package. This feature does not limit the processors to enter any of the core C-states. This default setting is "No Limit", all C-States supported by the processor are available. If set to "C0", no package C-state support.

Cluster on Die:

Cluster on Die (COD) mode logically splits a socket into 2 NUMA domains that are exposed to the OS with half the amount of cores and LLC assigned to each NUMA domain in a socket. This mode utilizes an on-die directory cache and in memory directory bits to determine whether a snoop needs to be sent. Use this mode for highly NUMA optimized workloads to get the lowest local memory latency and highest local memory bandwidth for NUMA workloads. Default is Auto.

Early Snoop:

Early Snoop mode for workloads that are memory latency sensitive or for workloads that benefit from fast cache-to-cache transfer latencies from the remote socket. Snoops are sent out earlier, which is why memory latency is lower in this mode. Default is Auto.

Thermal Profile:

The Baseboard Management Controller allows the user to adjust the fan speed manually. If the server is in a stressful environment, the CPU have high temperature, you can adjust the fan speed to High Fan Speed.

Memory Power Saving:

Selects the memory power saving mode. Depends on the selected mode, the Power Down clock mode, CKE and IBT are intialized accordingly, disable this feathe will keep memory in high performance mode.

C1E Support:

Enhanced C1 Power State boosts system performance.

Core C3:

Allows the BIOS to report the CPU C3 State (ACPI C2) to the operating system. During the CPU C3 State, the CPU clock generator is turned off.

Core C6:

Allows the BIOS to report the CPU C6 State (ACPI C3) to the operating system. During the CPU C6 State, the power to all cache is turned off.

CPU Performance and Energy Bias:

This BIOS option allows enable/disable to expose Energy Efficiency Policy control by Software feature to OS or not.

DCU Streamer Prefetcher:

DCU streamer prefetcher is an L1 data cache prefetcher. Lightly threaded applications and some benchmarks can benefit from having the DCU streamer prefetcher enabled. Default setting is Enable.