An affinity mask is a bit mask indicating which CPU Core a process should be run on by the scheduler of an operating system. Setting the affinity mask for FSX/P3D declassifies its default use of CPU cores, which can lead to better application performance.
Windows 7 - FSX SP2 - The following example uses an affinity mask value of 1364 applied to a Hexacore CPU with Hyper-threading enabled utilising cores #1 to #5, whilst running FSX SP2. Note how core #0 is almost at idle, allowing it to take care of processing other system requests and processes.
Windows 10 64-bit Version 1607 - P3D v3.1 - The following example uses an affinity mask value of 4095 applied to a Hexacore CPU with Hyper-threading enabled running P3D v3.1. Note how logical core #0 thread #0 is at 100% dedicated to P3D rendering tasks. The other logical cores and threads load balance the other P3D processing requests.
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