Automatically set Processor Affinity in Windows XP Professional

Is two better than one? Not necessarily, if your dual-core processor runs at less-than-effective efficiency with older programs. Here's how to optimize your processor settings to allow Windows XP Professional to run more smoothly by switching to just one core when running certain applications.

If you have a dual-core processor, you may discover that certain older applications that ran fine on systems with a single core CPU have problems running with two cores. For example, your application may suddenly begin maxing out the CPU usage at 100 percent, appearing to lock up. Windows XP Professional's Processor Affinity setting allows you to work around such problems by configuring older applications to use only one of the cores. Here's how to set it up:

  1. Access Task Manager.
  2. Choose the Processes tab.
  3. Right-click the process associated with the problem application.
  4. Select the Set Affinity command. (If you don't have a dual-core system, you won't see the Set Affinity command.)
  5. From the Processor Affinity dialog box, clear one of the CPU check boxes.

You could perform this manual operation every time you run the application, but the THG Task Assignment Manager (available for download from Tom's Hardware) allows you to create profiles that automatically assign applications to a specific CPU every time you run them.

Note: This tip applies only to Windows XP Professional.

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Greg Shultz is a freelance Technical Writer. Previously, he has worked as Documentation Specialist in the software industry, a Technical Support Specialist in educational industry, and a Technical Journalist in the computer publishing industry.

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