One Tweak to Rule Them All - How to set Affinity Mask Correctly

[Guest]

Interesting post, thanks! However, my good old AF=14 seems to work best for me and (oddly enough) the Adaptive options in the nVidia CP introduces stutters on my PC...? So I set it back to the default setting again. P3D was butter smooth already on my system but if never hurts to see if some fps can be gained somewhere. ^_^ Since tweaks are easy to implement and to remove again it's always worth a shot imho!

[SteveW 1,792]

Hey Toby, yes me too, I'm non overclocked and HT on.

[Juicehead 16]

I am running a 120hz monitor, do I need to worry about adaptive vsync?

[toby23 138]

Unless you can maintain 120 frames per second, yes.

http://www.geforce.com/hardware/technology/adaptive-vsync/technology

[Richard Sennett 2,499]

"Adaptive options"

 

This is probably not the end all on all of the different monitors out there - including all of the tweaks with all the different cpu's - gpu's - etc. one will have to tinker for Their own setup - no way around it - that being said it will be very hard for LM to come up with a fix that works for all - the only way around that is a sim built from the ground up - correct me if I am wrong but I doubt it

[charleslee201 19]

Getting a MUCH stable  overclocking with HT on  up to 4.8 mhz, temp max 80 a little bit higher  then   HT   off    HT off stable  max 4.5 :rolleyes:

[Domestos 10]

Thanks mate!

Even if this info is buried in the forums, taking the time to lay it out in a simple form is really helpful. It's hard sometimes to separate the wheat from the bull*****  (sorry)

 

 

 

 

Jim Harris

[Appliance 51]

LM/ Learning Centre/Tuning Guide

 

[JOBSCHEDULER]

AffinityMask=14 Non-Default entry. This entry will not exist in your Prepar3D.cfg file by default and must be added to the file.

Performance Tuning Tip:
Prepar3D runs best with one thread per physical processor core. By default, the application will create one thread per physical processor core. On quad core plus machines, the application will leave the first physical core open to allow the operating system, drivers, and other programs to run without interfering. Please note that many AMD processors that are marketed as 4 or 8 core processors really have 2 or 4 physical cores with something analogous to hyper-threading, so the default of one thread on every other core is still the intended behaviour. The easiest method for modifying the affinity mask is to open the windows calculator in programmer view, select the binary display mode, and flip the bits in the binary number displayed to select which cores the application should run on. Note that the cores are represented right to left. /dd> 

[SteveW 1,792]

Makes sense. What they are saying is that if an application spreads itself across all processors, it will inevitably bump into other threads. And so the Affinity Mask is used to partition the application onto a subset of cores, leaving the o/s to use the remaining less active cores. With HT on they are saying to use alternate LPs so that a full physical core is utilised per thread.

[jabloomf1230 2,445]

 

 

On quad core plus machines, the application will leave the first physical core open to allow the operating system, drivers, and other programs to run without interfering.

 

There are posts by LM staff on their forum indicating that they are now not that sure that this is true. At least for Win7/8 64 bit, the OS does such an efficient job of scheduling tasks, that it really makes no sense to disable 25% of the cores in P3d by default, just so some mythical OS use can operate unimpeded. On my setup, I've logged CPU use to a file during P3d sessions and I've never seen any other tasks (except TrackIR and ANS) use more than 1% of the CPU. Usually, the sum of all the other CPU use is less than 1%.

[SteveW 1,792]

Of course, if the application spreads itself across all the available cores, and OK one or more cores may get interrupted to run other infrequent threads, then it's no big deal, but it has full bandwidth of all the cores. However, if those threads are not utilising the full bandwidth of any core they can be partitioned onto less cores without impeding performance, and continue to avoid those infrequent o/s threads.

[StoreyedTrain 13]

OMG

 

I just put AffinityMask = "-G", and the program still worked, and all the cores were fully loaded !!!

 

Is it just me or are there more people that are getting a bit tired with all the AffinityMask-topics all the time.

Why does everyone always make a new topic instead of using an old one, and why not post in the tweaks/settings section ?

[toby23 138]

Because they're was no guide on how to work out the best value for your system. All those other posts didn't help me get the performance I have now.

[mickatmian 52]

Thanks for the useful information.

 

I use a i5 3570k @ 4.5 ghz which along with my gtx 780ti runs P3D 2.2 with most sliders to the right (with the usual micro stutters).

 

Affinity Mask set at 15 all cores via the P3D cfg file gives processor temps of 70+ degrees.

 

Now if I remove Affinity Mask from cfg file and set all cores via task manager temps stabilize in the mid to high 60's 

 

Can anyone confirm this as normal ?

 

Mick

[Chocorua 112]

Thanks for the useful information.

 

I use a i5 3570k @ 4.5 ghz which along with my gtx 780ti runs P3D 2.2 with most sliders to the right (with the usual micro stutters).

 

Affinity Mask set at 15 all cores via the P3D cfg file gives processor temps of 70+ degrees.

 

Now if I remove Affinity Mask from cfg file and set all cores via task manager temps stabilize in the mid to high 60's 

 

Can anyone confirm this as normal ?

 

Mick

 

Yes Mick, 15 will get all 4 cores running the sim and would seemingly raise temps. I use 14 (which is is done by default...if you leave the [JobScheduler] out of the config file. I see no performance difference between the two. Using a SB 2500K@4.2ghz.

cheers,