Why is AMD CPU/APU not always running at full speed?

Article Number: CPU-19
 

Under certain circumstances you may find that the AMD Processor or APU does not run at the highest frequency as stated in the specification. The frequency varies with the changes in the system’s workload.

 

NOTE! This article only addresses when your processor speed is constantly adapting to the system’s workload. In other words, when opening up several applications, the frequency may sometimes surge to max frequency, while at other times, it may slow down to lower levels when fewer applications are running. If the core speed stays at a low level and does not increase to max frequency with heavy workloads, a setting in BIOS or incompatibility with the motherboard may be the cause. Please check with your motherboard manufacturer for more details. Otherwise, you may consider possible hardware problems.

Speed monitor:

It is recommended using AMD System Monitor or AMD Overdrive to monitor the CPU speed. You may also try other third party utilities. Using different utilities to monitor CPU speed will help reduce errors due to monitor inaccuracy.  

 Monitor utility:

       AMD System Monitor: click on “Details”                                       AMD Overdrive: under Status Monitor-CPU status

            

If the utilities result in a large discrepancy in speed, the monitor utility may be the cause.  If all utilities detect approximately the same speed, the following help explain the displayed values:

 

Cause:

Processor or APU not running at the full speed can be a result of the AMD power saving feature Cool‘n’Quiet Technology (CNQ). Cool‘n’Quiet allows the operating system to match the processor utilization to the system workload, resulting in reduced power usage, lower energy cost and quieter PC operation. Cool‘n’Quiet technology adjusts the voltage, current and processor frequency in line with the system workload and the pre-set processor speed steps or states.  Different processors and APUs may have different numbers of power steps or states.

For example, an AMD Phenom™ IIX4 945 processor has several different Cool‘n’Quiet power states:

 

State

High

Medium

Low

Lowest

Frequency (MHz)

3000

2300

1800

800

 

 

Application Dependence:

An intense 3D action game would demand the full 3000MHz frequency of the AMD Phenom II X4 945 processor, but browsing the Internet and checking emails might only require the low speed of 1800MHz. When the computer is idle, CNQ will decrease the frequency to 800MHz. This would result in reduced power usage and a quieter system.

For more information about Cool’n’Quiet Technology, please visit the following link.

To enable Cool’n’Quiet Technology in your system, please check with your motherboard manufacturer.

 


Footnotes