Affinity Mask setting for dual core machines

[falconluan 2]

The contents of this topic is mainly for those who:1) has a dual core CPU;2) want to use Orbx GA airports or similiar;3) want to use facetracknoIR instead of real trackIR4) is a GA guy (actually a combination of item 2 and 3)If you are the one, it may be worthy taking a few moment to read below:Here in this forum, quad core CPU is almost standard config these days, so there is little discussion on how to optimize FSX performance with dual core machines, unfortunately, my CPU is a dual core one ...I've tested the affinity task setting on a dual core rig and would like to share some finding.As we all know, in fsx, the fiber processing is fixed on core0, which can not be changed by AM values. AM setting can only 'move' other threads (such as texture loading) to other cores. Actually, I think the threads are not moved, they are simply prohibited. This is based on what I've observed:1) Affinity mask set to 2, in binary, is '10', meaning that the threads like texture loading on core0 are turned off, leaving those work to core1 only. From the CPU usage we can tell that core0 usage is not very high but many wild varies, while due to the non-stop texture loading work, core1 usage is always close to 100%.2) Back out the affinity mask setting, fsx acceleration supports muti-core CPU by default, we can see both core0 and core1 usage are close to 100%, indicating core0 also has a lot of work to deal with such as loading texture.These conclusions can also be confirmed using the "Resource monitor", a utility which is provided by win7.With AM = 2, the fsx disk access instance(I don't know the unit of them, threads?) is significantly less than the AM = 3 caseSo, we have to balance:AM = 2, core0 only processes fiber, a certain number of frame rate increase, but reduced ability to load texure, so there will be more blurries.AM = 3, core0 shares the task of loading textures, less blurries, but because of there is less CPU cycles to run fiber on core 0, frame rate is hurt.FacetracknoIR is also a CPU hogger more or less, if there is no AM ​​= 2 setting, both cores' load is fairly heavy so the face track will be very jumpy. While setting AM = 2, core0 load becomes lighter, we can specify facetracknoIR to run on core0 only, the whole CPU burden is balanced, resulting a smoother tracking experience, but sacrifices some texture loading ability.Also we can play with the FIBER_FRAME_TIME_FRACTION to give core0 more time to load texture, but have not tested it yet.Orbx cessnock YCNK is my favourate, little blurries, face track, works like charm. Of couse, I'm not familiar with fsx schduler machanism, all the above are base on my observation and bojote and others great efffort on the fsx tweak.Sorry for my bad English.

[cianpars 1,158]

I would probably not use an affinity mask for a dual core. You are only using one core if you do.In SP2, AM3 is the same as having no affinitymask setting at all.There is a case for using AM14 on a quad core because that leaves core 0 free to run the os and background processes, thus reducing stutters. IAN

[falconluan 2]

I would probably not use an affinity mask for a dual core. You are only using one core if you do.In SP2, AM3 is the same as having no affinitymask setting at all.IAN

Yes, I know, using AM = 2 is meant to spare one core which can be used for face track.