Tag Archives: Intel Core 2 Duo

L2 Streaming Prefetch - The Tech ARP BIOS Guide

L2 Streaming Prefetch from The Tech ARP BIOS Guide

L2 Streaming Prefetch - The Tech ARP BIOS Guide

L2 Streaming Prefetch

Common Options : Enabled, Disabled

 

Quick Review of L2 Streaming Prefetch

Intel Core processors have a hardware streaming prefetch mechanism that automatically fetches an extra 64-byte cache line whenever the processor requests for a 64-byte cache line. This reduces cache latency by making the next cache line immediately available if the processor requires it as well.

When enabled, the processor will retrieve the currently requested cache line, as well as the subsequent cache line.

When disabled, the processor will only retrieve the currently requested cache line.

In a desktop system, enabling this feature improves performance as there’s a high probability of the processor requiring the next cache line as well as the currently requested cache line. It is therefore recommended that you enable the L2 Streaming Prefetch BIOS feature in a desktop system.

But in a server, the probability of the next cache line being required by the processor is lower than that of a desktop system. The higher cache miss ratio inevitably leads to higher bus utilization, which reduces the processor’s performance.

You will need to evaluate the performance effect of L2 Streaming Prefetch on your server and determine if it should be disabled or enabled for better performance. But servers should generally disable this feature.

 

Details of L2 Streaming Prefetch

L2 Streaming Prefetch is a BIOS feature specific to processors based on the Intel Core microarchitecture.

These processors have a hardware streaming prefetch mechanism that automatically fetches an extra 64-byte cache line whenever the processor requests for a 64-byte cache line. To be more specific, the adjacent cache line prefetch mechanism automatically fetches the adjacent cache line, essentially delivering 128-bytes to the processor, even if the processor does not request for the subsequent cache line.

This reduces cache latency by making the next cache line immediately available if the processor requires it as well. However, this increases bus traffic and can actually reduce performance if the processor does not actually require the second cache line. So, it is a double-edge sword.

When enabled, the processor will retrieve the currently requested cache line, as well as the subsequent cache line.

When disabled, the processor will only retrieve the currently requested cache line.

In a desktop system, enabling this feature improves performance as there’s a high probability of the processor requiring the next cache line as well as the currently requested cache line. It is therefore recommended that you enable the L2 Streaming Prefetch BIOS feature in a desktop system.

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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.

The higher cache miss ratio inevitably leads to higher bus utilization, no thanks to the fact that the processor prefetches an extra 64-byte cache line everytime it retrieves a single cache line. This increased bus utilitization reduces the processor’s performance.

You will need to evaluate the performance effect of L2 Streaming Prefetch on your server and determine if it should be disabled or enabled for better performance. But servers should generally disable this feature.

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Intel Dynamic Acceleration – The Tech ARP BIOS Guide

Intel Dynamic Acceleration

Common Options : Enabled, Disabled

 

Quick Review of Intel Dynamic Acceleration

The Intel Dynamic Acceleration BIOS feature is specific to the Intel Core 2 Duo mobile processor, introduced from the 4th-generation Intel Centrino Duo (Santa Rosa) mobile platform onwards. It is similar to the Intel Core i7 processor’s Turbo Mode feature.

When enabled, the processor will automatically ramp up the clock speed of one processing cores (while shutting off the other core) to improve its single-threaded performance while reducing its thermal output and power consumption.

When disabled, the processor will not overclock any processing core when single-threaded applications are running. Both its processing cores will run at the same clock speed.

If you are not already overclocking the Intel Core 2 Duo mobile processor, it is highly recommended that you enable this BIOS option to improve its performance with single-threaded applications. It will also reduce its power consumption and thermal output while running such applications.

However, you should disable this BIOS option if you are already overclocking the processor. Enabling it will very likely cause the processor to run one of the two cores at an excessively high clock speed and lock up the processor whenever a single-threaded application is running.

 

Details of Intel Dynamic Acceleration

The Intel Dynamic Acceleration BIOS feature is specific to the Intel Core 2 Duo mobile processor, introduced from the 4th-generation Intel Centrino Duo (Santa Rosa) mobile platform onwards. It is similar to the Intel Core i7 processor’s Turbo Mode feature. However, there are some fundamental differences in the way they work.

These Intel Core 2 Duo mobile processors can dynamically overclock one of their two processing cores to improve performance with single-threaded applications that would not be able to benefit from the second processing core. The second processing core is shut off completely to maintain or reduce the processor’s thermal output and power consumption.

This feature only kicks in when a single-threaded application is running. When multi-threaded applications are running, the processor will switch to its normal mode, with both processing cores running at their usual clock speeds.

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The Intel Dynamic Acceleration technology is different from the Intel Turbo Mode technology in that it shuts off the inactive core completely to reduce power consumption and thermal output. However, that prevents it from switching between the two cores to even out the thermal load. Thus, the first core would always be the active (and overclocked) core when single-threaded applications are running.

This BIOS feature is used to enable or disable the Intel Core 2 Duo mobile processor’s Dynamic Acceleration feature. It is usually enabled by default.

When enabled, the processor will automatically ramp up the clock speed of one processing cores (while shutting off the other core) to improve its single-threaded performance while reducing its thermal output and power consumption.

When disabled, the processor will not overclock any processing core when single-threaded applications are running. Both its processing cores will run at the same clock speed.

If you are not already overclocking the Intel Core 2 Duo mobile processor, it is highly recommended that you enable this BIOS option to improve its performance with single-threaded applications. It will also reduce its power consumption and thermal output while running such applications.

However, you should disable this BIOS option if you are already overclocking the processor. Enabling it will very likely cause the processor to run one of the two cores at an excessively high clock speed and lock up the processor whenever a single-threaded application is running.

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