If allocating more CPU cores to FSX will bring higher frame-rates sounds logical, the findings from recent experiments show a different result.
By applying different numbers to the AffinityMask command in fsx.CFG file, frame-rates achieved vary significantly. And most important, allocating more cores to FSX (including default setting without AffinityMask) doesn’t necessarily mean that framerate will be subsequently higher.
My CPU is an i7 930. After many testings, setting AffinityMask to:
* AffinityMask=20 (00010100; two cores) generates the highest framerate
* AffinityMask=84 (01010100; three cores) generates the second best FPS performance
However, setting to use fewer CPU cores will lengthen the time to load all FSX session, especially when a system has installed many complicated add-ons.
Above finding is true as long as no Saitek panels are used.
- When Saitek panels and switches are linked, AffinityMask=13 offers the best FPS performance
- When no Saitek panel is attached, AffinityMask=20 performs the best
Note: Above results are based on HD5870 card.