Using DSR, low latency and Sparse Grid AA

[Rogen 1,087]

This is for those "Tuners" out there, those who like to tune to maximise look and performance of P3D.

So... I've found no matter the sim (having come from FSX) I'm always looking for ways to improve performance, smoothness and the general look and feel and unfortunately have found not all go hand in hand.

There was a thread recently where the topic was around the sharpening filter in the latest NVidia drivers, with further mention of low latency settings and also the utilisation of a lower screen resolution for P3D, with up scaling to bring the lower resolution to std. desktop size.

https://www.avsim.com/forums/topic/561461-nvidia-image-sharpening/page/6/

I didn't go for the sharpen option as I use Luma sharpen in Reshade, however the use of low latency mode and up scaling sounded interesting and so decided to trial them out.

The Hardware:
GFX card is a satisfactory GTX 1070Ti with 8 GB ram overclocked to 2 Ghz, it's a good card and works well although it lacks in AA ability, meaning I cannot go above 4xSSAA without a high probability of maxing out the card to 100% and introducing stutters.
CPU is an AMD 2700x Ryzen also overclocked.
Monitor is a Dell 1920 x 1080 MHL 30 Hz capable.

The Scaling:
After reviewing the options in the current NVidia driver the decision was to trial DSR - Dynamic Super Resolution.
Enabling DSR requires several options configured in NVidia Control Panel.

1. Under "Display/Adjust desktop size and position" "Perform Scaling on: GPU" should be set and saved for the chosen monitor to run P3D.
2. Under "3D Settings/Manage 3D settings", in the Global TAB tick the "DSR - Factors", I chose 1.78 or 2560 x 1440 for my 1920 x 1080 native res monitor.
3. "DSR - Smoothness" was set to 75% for the trial.

With the above configured there was now a screen mode of 2560 x 1440 available to pick in P3D, which brings me to the first round of issues.

1. My custom 30 Hz modes were lost when using the DSR resolution resulting 60 Hz and no P3D vsync smoothness. Could use RTSS, but really wanted 30 Hz.
2. I only wanted to use the DSR screen mode for P3D, however the desktop resolution changes with P3D's resolution meaning I would need to change the screen mode back to 1920 x 1080 @ 60 Hz manually.

Both the above issues were solved via a little application I already use named dc2.exe (Display Changer 2) called from P3D's start script.

Display changer uses an xml file with the required display mode so that when called in the script P3D would automatically start in a 1920 x 1080 30Hz screen mode and then exit back to a 60 Hz screen mode when P3D shuts down.

A little hand modification of the xml to include <size width="2560" height="1440"/> resulted in P3D's starting in the DSR mode @ 30 Hz and automaticaly switching back to 1920 x 1080 @ 60 Hz when exited.

https://www.avsim.com/forums/topic/511257-resolved-running-prepar3d-at-30-hz-automatically

The P3D start script part:

The script line below checks for a running P3D and only runs the app should a running P3D not be found.

tasklist /nh /fi "imagename eq Prepar3D.exe" | find /i "Prepar3D.exe" > nul ||(START "PREPAR3D" /ABOVENORMAL /D "H:\Lockheed Martin\Prepar3D v4" /I "E:\FSX Addons\DisplayChanger\dc2.exe" -configure="E:\FSX Addons\DisplayChanger\P3D30HZ.xml" "H:\Lockheed Martin\Prepar3D v4\Prepar3D.exe")

Low Latancy Mode:
Set this to Ultra in the NVidia Control Panel and then in the NVidia Inspector set Silk Smoothness to 0x00000001. Reduces the latency of triple buffering while still smoothing out edge case stutter bumps.

Antialiasing:
A bit of trialling showed good results from the above config, however with AA @ 4 x SSAA the GPU was maxing out at times introducing stuttering, 2 x SSAA resolved the maxing out and got rid of the stuttering. But... 2 x SSAA doesn't look as good as 4 x SSAA.

Back into NVidia Inspector and set the following for my Prepar3D profile.

1. Antialiasing - Mode                                          Enhance the application setting
2. Antialiasing - Transparency Supersampling    2 x Sparse Grid Supersampling

Now there is a trick to get the above AA working in P3D (and other apps/games as well according to what I've read) and that is to set P3D AA to an MSAA value of 4 e.g. 4 x MSAA.

Result being 2 x SGSSAA is a good compromise between 4 x SSAA and 2 x SSAA, tuning the GPU use to a high use result without maxing to 100%.

Results:
And trialling is so far so good, P3D looks great in DSR 2560 x 1440 @ 30 Hz, there is noticebly less latency yet flight is still smooth and AA now maxes at ~85% GPU use instead of a 100% while offering improvement over 2 x SSAA. Plus when I exit P3D my screen mode automatically drops back to 1920 x 1080 @ 60 Hz.

I've recorded a vid of a flight using the above configuration which is uploading to Google atm and I'll post in the vid forum for those who want to have a look.

I hear NVidia may be releasing a 3000 series GPU next year and cheaper than the current crop of 2080s, might be more affordable to bump up the AA to much higher levels with a new card in the coming year.

Cheers

 

[QuaxTheSnoopie 16]

On 11/17/2019 at 6:43 AM, Rogen said:

...to set P3D AA to an MSAA value of 4 e.g. 4 x MSAA.

Result being 2 x SGSSAA is ...

Shouldn't the level of MSAA and SGSSAA be the same ?
https://steamcommunity.com/app/299740/discussions/0/2132869574264276328/
"- It requires that you have MSAA set to the same level of anti-aliasing as the level of SGSSAA you want to use."

https://www.overclock.net/forum/69-nvidia/1250100-nvidia-sparse-grid-supersampling.html
"You must set the Sparse Grid Sample number to the exact same amount of multi-samples. In other words if you are using 4XSparse Gride you also MUST use 4xMSAA in the profile. Otherwise you will end up with a blurry mess."

[Rogen 1,087]

23 hours ago, QuaxTheSnoopie said:

Shouldn't the level of MSAA and SGSSAA be the same ?

Should it?

The testing I did showed results that were noticably better when MSAA x4 was used, both in looks and in higher GPU use % without maxing to 100% use and better than MSAA x4 alone.

Testing was carried out at a airport parking area where rotating around the aircraft whould demonstrate edge stepping and shimmer as well as medium to very high GPU use.

FYI - the parking area was NZMF (Orbx) just in front of the information signage and has mountains, trees, was clouded and also many thin edge types of objects such as wire fencing and static a/c where edge stepping on the wings and copter blades was an indicator of output.

Remembering the goal was tuning the GPU for good looks without maxing the GPU to 100% using the % as the gauge across a repeatable test example.

Post tuning was a flight from NZMF to T004 and back to confirm how well it performed (was enough to make me happy with the results for my own brand of flying).

You can see the NZMF -> T004 part of the flight here

Of course going x8 SS was the best looking, however such values maxed the GPU to 100%+ killing frame rates totally.

As NVidia may be releasing a 3000 series GPU next year that's more affordable than the current crop of 2080s, it should be ideal as a new card to bump up the AA to much higher levels.

But for now my (now tuned) 1070Ti will do.

Cheers

 

[Christopher Low 5,352]

I use 4xSSAA in P3D v4, which is good enough fo be acceptable to me. However, it certainly is not as good as 4xSGSS AA plus 8xS AA was in P3D v3 (via Nvidia Inspector).

Is SGSS AA now an option in Nvidia Control Panel? If so, I may consider using that with DSR after I have built my new PC over Christmas.

[AnkH 2,261]

Well, I do not know in which weather conditions you guys fly, but on my rig, using 4xSSAA kills the performance in cloudy weather completely. Even though I use the lowest possible resolution for clouds installed by REX and I limited ActiveSky to three cloud layers only. That is why I now switched to 8xMSAA for the sake of a fluent sim even in heavy weather conditions...

[Christopher Low 5,352]

I fly in calm weather and clear skies, and @ 1920x1080 resolution.

Edited December 5, 2019 by Christopher Low

[Rogen 1,087]

2 hours ago, AnkH said:

Well, I do not know in which weather conditions you guys fly, but on my rig, using 4xSSAA kills the performance in cloudy weather completely. Even though I use the lowest possible resolution for clouds installed by REX and I limited ActiveSky to three cloud layers only. That is why I now switched to 8xMSAA for the sake of a fluent sim even in heavy weather conditions...

Well, I have Rex Texture Direct Extended with Soft Clouds with DXT compression and use middle resolutions for the cloud textures.

Also have Volumetric Fog unchecked on P3D, Cloud draw distance set to 90mi and Cloud coverage density set to max and have 5 layer clouds in AS.

Plus run PrecipitFX with a slightly hand modified PrecipParticle.fx shader as well as running TomatoShade.

Rain and cloud is for the most part not a problem, and when it is I've found killing AS and restarting to resolve (it's like AS loads up and bottlenecks and a restart resolves).

 

4xSSAA was typically fine when I ran 1920x1080, however was a no go at 2560x1440 with my 1070Ti, hence why I was experimenting with combinations of SGSSAA via the Nvida Inspector.

[Rogen 1,087]

A screen pic showing my rig running @ 1920 x1080 30 Hz vsync in the A2A Commache with heavy cloud and lots of rain and mangaing 30 fps nicely.

It's all about the tuning.

Cheers

This pic is on pause but shows the rain a bit better

 

Edited December 7, 2019 by Rogen