In Windows XP and Windows Vista, applications by default run on all available cores of the processor, if you have a dual or quad core processor, then you can set affinity to an application to control which core of the processor an application can use, in this way you can assign one application or a program to use only one processor while other application can run on other processor.Processor Affinity is the process by which particular tasks on the computer are scheduled and accomplished. A computer’s processor (CPU) creates a queue for tasks to be performed and determines, by level of importance, which tasks should be performed first and which can be performed later. To change these settings, you must adjust your computer’s processor affinity.

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.The setting allows you to work around such problems by configuring older applications to use only one of the cores.

Although you cannot set priority to system services but you can set affinity to applications like Google Chrome, Firefox or any Anti-Virus, in this way you can achieve a good overall performance.

Steps to set set affinity to applications in Windows XP

Press Ctrl+Alt+Delete to open Windows Task Manager, and go to the Processes tab and look up for the process name that you want to set the affinity for