CPU Adjacent Sector Prefetch – BIOS Optimization Guide

CPU Adjacent Sector Prefetch - BIOS Optimization Guide

CPU Adjacent Sector Prefetch

Common Options : Enabled, Disabled

 

Quick Review

CPU Adjacent Sector Prefetch is a BIOS feature specific to the Intel processors (from Pentium 4 onwards), including Intel Xeon processors.

When enabled, the processor will fetch the cache line containing the currently requested data, and prefetch the following cache line.

When disabled, the processor will only fetch the cache line containing the currently requested data.

In a desktop system, CPU Adjacent Sector Prefetch improves the processor’s performance since there’s a high probability of the processor requiring the next cache line as well. It is recommended that you enable this BIOS feature in a desktop system.

But in a server, this feature may actually degrade performance since data requests in servers are of a more random nature. You will need to evaluate the performance effect of CPU Adjacent Sector Prefetch on your server and determine if it should be disabled or enabled for better performance. But servers should generally disable this feature.

 

Details

CPU Adjacent Sector Prefetch is a BIOS feature specific to the Intel processors (from Pentium 4 onwards), including Intel Xeon processors. When one of these processors receives data from the cache, it can also prefetch the next 64-byte cache line. This may reduce cache latency by making the next cache line immediately available if the processor requires it as well.

When enabled, the processor will fetch the cache line containing the currently requested data, and prefetch the following cache line.

When disabled, the processor will only fetch the cache line containing the currently requested data.

In a desktop system, CPU Adjacent Sector Prefetch improves the processor’s performance since there’s a high probability of the processor requiring the next cache line as well. It is recommended that you enable this BIOS feature in a desktop system.

But in a server, this feature may actually degrade performance since data requests in servers are of a more random nature. The probability of the next cache line being required by the processor is lower than that of a desktop system. If the processor prefetches the second cache line and it is not required by the processor, it is discarded and the processor requests for the data it needs. This incurs a slight penalty in performance.

You will need to evaluate the performance effect of CPU Adjacent Sector Prefetch on your server and determine if it should be disabled or enabled for better performance. But servers should generally disable this feature.

Go Back To > The BIOS Optimization Guide | Home

 

Support Tech ARP!

If you like our work, you can help support our work by visiting our sponsors, participate in the Tech ARP Forums, or even donate to our fund. Any help you can render is greatly appreciated!

Comments

comments

About The Author

Related posts

Leave a Reply

%d bloggers like this: