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Posted on Mar 28, 2008 in PC Maintenance, Troubleshooting Compatibility | 9 comments

Setting CPU affinity for legacy games and applications

Performance issues running an old game or application on your modern PC? Try setting the CPU affinity. If you have a dual or quad core computer and you want to run older games or applications, then in some cases you may experience degraded performance or crashes. Sometimes these problems can be solved by setting CPU affinity / processor affinity for the affected application. CPU affinity, what’s that? This refers to how many CPU (Central Processing Unit), ‘cores’ an application runs on. Dual and quad core processors have two or four processing units on one chip! If your game or application was written before dual and quad core systems were commonplace, it may not have been tested properly on these systems and therefore suffer performance problems when run on more than one processor core. To solve this problem, we can make the software run on only one processor core.

Setting processor affinity is a little more fiddly than changing compatibility options. We’ve tried to make the process as easy as possible but it may be difficult for less experienced users. We recommend that you watch the video on understanding file paths if you have difficulty with some of the terminology in the video.

To start the video presentation, please click on the picture below.

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Additional notes

The affinity.txt document mentioned in the video can be downloaded here. Right click on the link and choose “save as” then place the file on your desktop or somewhere where you can easily access it when following the tutorial.

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  1. It failed and said “Windows can not find ‘file:///C:/Windows/System32/cmd.exe%20/C%20START%20%22steam://rungameid/361420%22%20/high%20/affinity%201’. Make sure you typed the name correctly, then try again.” I’m confused.

    • You’re pointing it to the Steam shortcut for your game, you need to find the games actual executable, which will probably be in your Steam folder, typically C:\Program Files (x86)\Steam\steamapps

  2. I have a program that was developped for Win3.1 (visuwin).

    I cant find out a proper way to run this; any suggestions?
    When following your tutorial i at least get it to do something: opening CMD titled “administrator: visuwin”

    help would be greatly appreciated.

  3. Didn’t work on my PC, win 10 with AMF FX 8 cores.

    • What exactly went wrong?

      • The program still uses the 8 cores. I tried both methods explained on the article, without sucess.

        • Are you certain? Never known this method to fail.

          • Yes, pretty sure. Tried to play Silent Hill 2, that has soud problens with multiple cores. Even with the command lines, the games still has the soud problems, so I went to the Task Manager, Details and on the EXE of the game it shows that it is using all 8 cores. Changing it manually resolves the problem. But it is a bit of a pain doing this everytime…

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