C1 Enhanced Mode; Execute Disable Bit; Adjacent Cache Line Prefetch; Hardware Prefetcher - Silicon Graphics Altix XE250 User Manual

5: BIOS Settings

C1 Enhanced Mode

Execute Disable Bit

Adjacent Cache Line Prefetch

Hardware Prefetcher

Set Max Est CPUID = 3

IP Prefetcher

Direct Cache Access

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Select Disable to disable the Standard C1 Halt State, which will partially turns off the CPU internal
clocks to conserve energy and prevent system overheating when the OS is idle. Select Enable to
use the Enhanced C1 Halt State to lower the CPU clock frequency and the supply voltage before
turning off the clocks.
Set to Enabled to enable Execute Disable Bit and allow the processor to classify areas in memory
where an application code can be executed and where it cannot, and thus preventing a worm or a
virus from inserting and creating a flood of codes to overwhelm the processor or damage the
system during an attack. The options are Disabled and Enabled.
The CPU fetches the cache line for 64 bytes if this option is set to Disabled. The CPU fetches both
cache lines for 128 bytes as comprised if Enabled. The options are Disabled and Enabled.
Set this option to Enabled to enable the hardware components that are used in conjunction with
software programs to prefetch data in order to shorten execution cycles and maximize data
processing efficiency. The options are Disabled and Enabled.
When set to Enabled, the Maximum Extended CPUID will be set to 3. The options are Disabled
and Enabled.
Set this option to Enabled to use the feature of IP Prefetch to speed up data processing. The options
are Disabled and Enabled.
Set to Enable to route inbound network IO traffic directly into processor caches to reduce memory
latency and improve network performance. The options are Disabled and Enabled.
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