Windows 7 - Processor Affinity - Set for Applications

**Brink**

How to Set Processor Affinity to an Application in Windows 7

Information

By default, Windows 7 and Vista runs an application on all available cores of the processor. If you have a multi-core processor, then this will show you how to set affinity to an application to control which core(s) of the processor an application will run on.

If the application and CPU supports Symmetric Multiprocessing (SMP) or HyperThreading (HT), then Windows will automatically adjust the application's usage of each processor core for the best performance. You will not gain much, if anything, from manually changing the processor affinity for these type od applications.

It is strongly NOT RECOMMENDED to change the Process Affinity for System Processes.

Note

The affinity changes you make to the current instance of an application or process are only temporary and not set permanently.

Once you close the application or restart your system, Windows forgets your set affinity and automatically sets back the default affinity of the application running on all available cores of the processor.

Here's How:

1. Right click on a empty space on the taskbar and click on Task Manager, OR press CTRL+SHIFT+ESC.

2. If UAC Permission is Required to Run the Application
A) Click on the Processes tab in Task Manager, then click on the Show processes from all users button. (see screenshot below)

B) If prompted by UAC, then click on Yes (if administrator) or enter the administrator's password (if standard user).

C) Continue on to step 3

3. Click on the Applications tab, then right click on the application that you want to set processor affinity of and click on Go to Process. (see screenshot below)
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4. In the Processes tab, right click on the application's process, then click on Set Affinity. (see screenshot below)

5. Check or Uncheck which CPU processor core(s) you want to be allowed or not allowed to run the application on, then click on OK. (see screenshot below)
NOTE: CPU-0 = Core 1, CPU-1 = Core 2, etc.......

6. Repeat for any other applications that you wish to change the processor affinity for.

7. When finished, close Task Manager.

That's it,
Shawn

Related Tutorials

**601122** · 07-13-2010

I don't have an option in my processor drop down menu to change the affinity setting. A fix to an issue I am having from other forums is to change this but there is nothing under set priorty. Any ideas??

**Brink** · 07-13-2010

Hello 601122, and welcome to Seven Forums.

Is the Set Priority menu empty for all of the listed proccesses, or just this one?

For now, you might see if running a sfc /scannow command may be able to help.

**601122** · 07-13-2010

As you can see there is no option under the set priority to change the Affinity setting. My knowledge is very basic.

Thanks

**Brink** · 07-13-2010

601122,

I know this may seem silly, but did you move the mouse pointer over Set Priority to expand the arrow menu?

**601122** · 07-14-2010

Hi thanks for assistance, yes it gives 6 options, real time, high, above normal, normal, below normal and low. Cheers.

**Brink** · 07-14-2010

That's great news. You're most welcome.

**mickey megabyte** · 07-15-2010

you can 'permanently' set a program's affinity by creating a .bat batch file in the same folder as the program, with the contents:

Code:

start /affinity 1 program_name.exe

this will force the software to use only cpu core 0. use ... /affinity 2 ... to specify cpu core 1 etc

you should then modify the program's start-menu and/or desktop shortcut to point to your newly created batchfile.

a tiny drawback is that you will see a small cmd window briefly flash on the screen before your program opens.

-------------------------------------------------------

for extra performance, you can add /high to give the application a higher cpu priority.

Code:

start /affinity 1 /high program_name.exe

(Brink, if you can rewrite this to make it clearer, then please do.

)

Windows 7 - Processor Affinity - Set for Applications

Processor Affinity - Set for Applications

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