Ah, the age old question.  I just installed FSX boxed on a new build which uses a i7-13700K CPU.  My last processor was a i5-3570K, so the affinity mask setting was easy; 14.

Now the new processor has 16 cores (8 performance and 8 efficient).  It also has hyper-threading, which my old i5 didn't.

I know one recommendation is to turn off Hyper-Threading, but since this machine will also be used for MSFS as well as Visual Studio, OBS, etc. I'm reluctant to do that unless there is a way to make it FSX specific.  That leaves with with the big question of what do I set the Affinity Mask to within FSX and does it even matter anymore?  I would appreciate any guidance.

Thanks..

Edited August 11, 20232 yr by airernie

Personally, I don't think using an affinity mask is necessary with fast CPU's that have 8 or more physical cores. 

If my FSX experience is anything to go by with more modern CPUs, you would keep hyperthreading on for the benefit of the system overall plus other applications (especially in your case) and then use something like Prio (or the affinity mask, though I have only used Prio) to enable FSX on Cores 0 and 1 and from there 2, 4, 6, 8, 10, 12, 14, thus leaving out cores 3, 5, 7, 9,11,13 and 15. Doing this provides the best performance and no hyperthreading induced stutters or performance drops (which happen with both Ryzen and Intel CPUs if you do not disable the odd numbered cores beyond core 1). You will still benefit from both core 0 and 1 being active though - the problems only start with the second and subsequent cores.

Those settings (0,1,2,4,6,8,10,12,14) work on both Intel and AMD Ryzen 8 core CPUs btw.

The affinity mask for Ryzen and Intel 8 physical / 16 logical would then be

 [JOBSCHEDULER]
AffinityMask = 21847

if I am not mistaken however as mentioned I only use Prio (to set precisely the same core configuration) since Prio has the advantage of letting me set affinities, CPU and I/O priorities permanently and for all processes - not just FSX.

Edited August 12, 20232 yr by JonP01

Good information.. Thanks..

Not sure AM setting will matter too much to be noticeable.

I'm real curious to hear of your performance gains from your older i5 to the new i7.

VeryBumpy: Will do as soon as get the new installation on par with the older one. Still installing some visuals and aircraft and adjusting the settings.