Using 14 or 15 makes no difference as Core 0 will be in use anyway. The affinity mask only restricts fsx to using the 4 real cores and turns off the virtual cores.Better still set up an overclocked bios profile (if available) to turn off hyperthreading and overclock more when using fsx - just my 2 cents.John Ellison

Thank you!

Derian it shouldn't make any difference on the i3 as it's dual core (4 thread) anyway and fsx would use all so no absolute need to use affinity mask but you could try an affinity mask of 2 or 3 to turn off the 2 virtual cores (2=0010 3=0011).Just try it with and without and see if it makes any difference at all - maybe it will maybe it wont.I had fsx running very well on a 3Ghz core2 Duo and an Nvidia 9600GT agp card as long as I wasn't too aggressive with the settings.John Ellison