I have achieved liquid smoothness at relatively a low frame rate, in all planes I use (PMDG 738, AS CRJ700, B78X, TBM930), everywhere including the most complex departure AND arrival terminals.  It is rare now to get even 1 stutter anywhere from gate to gate and this includes during taxi, turning and all AI and ground traffic are ultra smooth--GSX Pro objects still gets the occasional stutter.  All settings on Ultra, system specs in signature.

Known Possible Limitations

• Probably need a Gsync display, though perhaps Freesync will work for this as well.
• I don't use VR, so this may not work well there because this method allows for relatively low frame rates with zero loss of fluidity.
• I only have my hardware to test on:  so Intel CPU, NV GPU, etc.

Basics

• ALL other methods of Vsync or framerate lock are OFF, except:  RTSS Framerate Limiter w/ Edge Sync w/ Passive Waiting enabled
  • This method delivers incomparably low frame time variance (FTV) which I learned is the pathway to ultra-smooth animation at modest frame rates.  I'm convinced there is an inverse relationship between framerate and FTV such that the lower the framerate the more low FTV matters.  Brute force with RTX4000 w/ its frame generation obviates this some because the higher the frame rate the less it matters to have ultra low FTV in the perception of fluid animation.
  • A Gsync display is required to get rid of a tear line that appears with this method of frame rate limit (FreeSync may work, unable to test)
• Process Lasso
  • All resources off the main thread.  I'm pretty sure this has eliminated a couple of persistent sources of stuttering (ATC related, audio related, primarily)
  • MSFS Process Priority at High
  • MSFS I/O at Critical
• FSLTL's limiter to control traffic density as this has a big impact on the main thread.
• NV Control Panel:  all default global, except Low Latency is set to Ultra
• GeForce Experience had NO adverse effects on smoothness nor stuttering so I use this for its filters and video recording
• I discovered using Render Scaling different from default 100 creates a subtle but recurrent 'shimmer' for lack of a better word--kind of a sudden shaking back and forth, that is subtle be there.

TBH in the PMDG 738 I tend to just leave T-LOD at 130 to allow me into any terminal anywhere, all Ultra settings save T-LOD, with zero stuttering anytime including taxi.  I've accidently left it at 200 after flying in the AS CRJ which does fine at 200, and even then almost no stutters anywhere.  But truthfully, T-LOD at 130 v 200 is not an earth shattering difference anyway.  

Here's the counterintuitive part:  with my Gsync Ultimate display I can run frame rates well above where I do, which is right at 33 or 34 via RTSS' limiter.  I've run at 50FPS as well, and there is no visual benefit whatsoever and that is because of the ultra-low FTV in both scenarios, when syncing via this method.   In-sim Vsync, NVCP Vsync, do not create what you see in the 2nd screenshot below.  And in fact from Cpt_Piett's testing you don't get this kind of FTV with frame generation either--but I think when you have frame rates of 80 or 100 ultra low FTV won't matter so much.

Here we are in the PMDG 738, frame rate unlocked, thru a Gsync display, with a variable frame rate averaging around the low 40's.  Note the FTV. 

Now here's the same flight however locked at 34 via RTSS.  Visually, this is superior to what you see above despite the 24% lower frame rate!  Superior panning, turning, fluidity etc

As mentioned I can run the RTSS limiter well above my default 33 or 34 when conditions permit, but again there is zero benefit from this.  And the downside is, and I believe this is relevant to my complete lack of stuttering even flying into KLAX in the PMDG 738:  you lose the headroom you get from not running wide open and I believe this becomes a source of inability to keep up with sudden demand, and so ensuing stutter.  So typically now my mainthread (via MSI Afterburner's OSD, which isn't precise, but useful still) sits around 70% instead of 97% when unlocked, and GPU around 70% instead of 99% when unlocked.  My sense is this leaves a little headroom to absorb spikes with.

It is a total game changer to have liquid smooth performance everywhere, in any plane.  This has been so awesome I had to post it in more detail for those who might not have experienced Nirvana yet and bonus--an RTX4000 series card is not needed, at least for 3440x1440, and no VR.  Follow the method carefully to give it a fair test.

Here's what RTSS should look like.  Note we're not using Scanline sync, just Framerate Limit:

Click Setup, and scroll to Compatibility Properties:

Cool bonus:  you can toggle the limiter on and off while flying w/o stopping by using RTSS' HotkeyHandler.dll.  You can see I use Num * button on to toggle the limiter off and on.  This is useful to see where you would be unlocked.  And if I'm at an ultra demanding airport where the unlocked rate is essentially to my lock at 33/34 I'll run unlocked until up and away, then a simple button press returns me to limited (with its superior FTV and lower demand on hardware):

I hope this helps others it's been an absolutely astonishing finding and has made all flights a joy.  I tried all other methods to get here and none match this.  I'll not be upgrading my hardware anytime soon! 

Edited December 29, 20223 yr by Noel

Thanks.

 

What do you mean with:

 

• Process Lasso
  • All resources off the main thread.  I'm pretty sure this has eliminated a couple of persistent sources of stuttering (ATC related, audio related, primarily)
  • MSFS I/O at Critical

7 minutes ago, altenae said:

Thanks.

What do you mean with:

• Process Lasso
  • All resources off the main thread.  I'm pretty sure this has eliminated a couple of persistent sources of stuttering (ATC related, audio related, primarily)
  • MSFS I/O at Critical

Those are configurations possible w/ PL, which is an app you can purchase from the developer.  For my 8 core 9900K core 07 is the MSFS main thread.  So I have all other processes running on Core0 thru Core06, and MSFS on Core0 thru Core07.  Process Priority at HIGH and I/O at Critical are other settings possible in PL.  

Edited December 29, 20223 yr by Noel

8 minutes ago, Noel said:

Those are configurations possible w/ PL, which is an app you can purchase from the developer.  For my 8 core 9900K core 07 is the MSFS main thread.  So I have all other processes running on Core0 thru Core06, and MSFS on Core0 thru Core07.  Process Priority at HIGH and I/O at Critical are other settings possible in PL.  

Thanks.

Will core 07 always be the main thread in your situation ?
Or does it change bij restarttng the sim  etc. ?

6 minutes ago, altenae said:

Will core 07 always be the main thread in your situation ?

Yes

Again?

You consider your hardware system as modest? 

I guess perhaps based on the current "state of the art" systems, perhaps so.  However, yours is way beyond my meager, modest system/hardware.

40 minutes ago, Noel said:

Those are configurations possible w/ PL, which is an app you can purchase from the developer.  For my 8 core 9900K core 07 is the MSFS main thread.  So I have all other processes running on Core0 thru Core06, and MSFS on Core0 thru Core07.  Process Priority at HIGH and I/O at Critical are other settings possible in PL.  

Confused - You have ALL cores disabled for FlightSimulator.exe except core 7 ?  

Tony, " MSFS on Core0 thru Core07"

Just now, Noel said:

Tony, " MSFS on Core0 thru Core07"

right ok - so you removed Core 7 from other processes ?  How do you know Core 7 is your main MSFS thread ?

7 minutes ago, beechcaptain said:

You consider your hardware system as modest? 

Well it's now 3y/o, compared to RTX 4000 series with its frame generation, and I9-12900 or 13900, or 7950x3D and those folks can brute force their way to Nirvana but very fortunately it's not necessary (for the conditions I'm addressing, not for VR, etc).

2 minutes ago, Tony P said:

right ok - so you removed Core 7 from other processes ?  How do you know Core 7 is your main MSFS thread ?

MSFS runs on the last core be it logical or actual, and this is easily corroborated using any number of core load monitors such as MSI AB's OSD, and Process Lasso shows dynamically all cores running.

The primary reason for this was to get certain processes away from the main thread, in particular audiodg.exe I think it is called and a few others.  I noticed this was the pathway to losing the associated microstutter when ATC text/voice happens.  These may contribute to other sources of microstutter or what have you, and there is no downside except you must run PL before starting MSFS else it may/will not load.  So that is the last step in my flight setup, to run PL.

1 minute ago, Noel said:

MSFS runs on the last core be it logical or actual, and this is easily corroborated using any number of core load monitors such as MSI AB's OSD, and Process Lasso shows dynamically all cores running.

The primary reason for this was to get certain processes away from the main thread, in particular audiodg.exe I think it is called and a few others.  I noticed this was the pathway to losing the associated microstutter when ATC text/voice happens.  These may contribute to other sources of microstutter or what have you, and there is no downside except you must run PL before starting MSFS else it may/will not load.  So that is the last step in my flight setup, to run PL.

Cool thanks - I'm also running a 9900K with a 3080Ti - will report back with results at some point.  

Wait a minute: a 3080ti is now considered "modest hardware"?

What am I missing?

25 minutes ago, Ricardo41 said:

Wait a minute: a 3080ti is now considered "modest hardware"?

What am I missing?

It's a slouch compared to RTX 4090, or 4060, or what have you with its Frame Generation and massive VRAM--just go ask the guys who bought one!

Thanks, I changed the title (twice!) in case someone else (you're the 2nd of two in just a few replies) focuses on the definition of modest and so may miss the entire point of the post.  Of note my 3080Ti rarely goes over 60-70% in the most demanding settings which tells me on no uncertain terms this approach works with lesser GPUs.

Edited December 29, 20223 yr by Noel