Assetto Corsa not butter smooth whatever i do

[Haris1977]

Greetings.

I didn't know were to upload this thread and sorry if this is the wrong place.

I have a strange problem with all of the versions of AC (1.14, 1.15, 1.16, 1.16.2, 1.16.3 etc). I know that this is kind odd but i do not have butter smooth gaming experience. I have a very sensitive eye in terms of fps/jerkiness. It is an annoying jitter in the visuals. Note this is separate from stuttering. It is a constant uneven framerate, look at the scenery in a turn to see it.

The only version that i have a butter smooth experience (this sounds very odd i know) is the old 1.7.1 version (!!)

I really can't understand why this is happening. My fps are constantly way above 60 fps (> 120 fps in game with all settings to ultra), so fps is not the problem. Even though i have high fps i do not see butter smooth movement (i can see that "jerkiness"/"jittering" in movement especially in "turns"). Same happens even if i turn sync on/off, sync to 60 fps, sync to 61, sync to 83 fps etc, lowering the graphics, removing steering wheel, etc. Even with graphics to low, same happens.

Truth 1: My eye is very sensitive in fps, that's why i can notice it (my friend didn't notice it at all for example). All statistics show no problem

Truth 2: I have a really old 24 inch Dell monitor, but i m not convinced that the monitor is my problem. In other games (ACC, DR2, Race Room Experience i have butter smooth gameplay). With same monitor, same specs.

Truth 3: The problem does not happen in a) benchmarking b) replays

Truth 4: Lots of users face this problem. I recon it is smth with the in - game inability to keep the frames (frame pacing error). It is irrelevant to low or ultra settings/resolution etc

Any thoughts about that?

My log files here for anyone interested: https://www55.zippyshare.com/v/ywyjMj3t/file.html

My rig: ryzen 5 2600x, rtx 2070, 16 GB Ram, latest gfe and driver (3.19.0.107 and 431.60 as we speak)

 

[Vintagedriver01]

1). ok
2). guess an 60hz monitor try to cap your game also around 60FPS. Some are even going to cap it to 55hz.
3). that is because its playing a video
4). you say it, so who am I to discuss this.

Disable all the mods in your game even CM, gameHub and the cars/tracks, keep the game original. Try again, but now logging ALL your CPU Cores & frametimes. MSI afterburner is a fine piece of software of loggingtool and does have an great OSD. I still think one of your cores is overflowing and so brings in an fluctuating in your frame time. If you are sensitive it is that you are notice.
Another experiment you should consider, is doing a test now disabled the Vsync and experiment with all the different Vsync modes in nVidia CP.

 

[Fleskebacon]

I am experiencing the exact same as you describe. Nothing wrong to be seen with frame times or fps, but still the jerky/juddering scenery, even with Gsync.

My friends don't see it, but I'm not imagining it.

Did you ever figure this out?

 

[Darko Jovanoski]

I know it's old thread but while searching for answers I came here. I can't find the issue why is this happening. Even playing on 165hz with gsync I have this problem but the most interesting part is that is not happening when I have opentrack running and using headtracking. Enabling neckfx without opentrack doesn't fix this. Really weird! I don't want to drive with headtracking all the time. Did someone found fix for this?

 

[Captain Beardface]

Are you using the fps limiter in CM? I've found it to cause stutter. Better to use the one in nVidia control panel if you have an nVidia card.

 

[Darko Jovanoski]

Are you using the fps limiter in CM? I've found it to cause stutter. Better to use the one in nVidia control panel if you have an nVidia card.

Belive me I tried everything but as I said those panning issues are gone only if I use headtracking. And yeah I noticed that limiting fps is worse in cm than in Ncp but issue is persistent.

 

[IMEAN]

I am having the same problem... 7800XT and 13600k. Latest CSP, no sol.

Exactly has "harris" describes, if you look at the scenery or kerbs while making a turn and there is some weird stuttering going on.
It also seems to me that during watching a replay the stutter is not in effect.

I tried everything: Vsync ingame on/off vsync driver on/off, frame limiter via driver/content manager/RivaTunrStatistics server or unlimited fps.

Turned off freesync, Turned off all video setrtings and more.

My rig could run 300 fps in hotlap mode but the problem remains even then no matter what.

A little workaround for this problem is to enable motion blur. The stuttering is still there but not as visible because everything is blurrred a bit.

Does anyone know a real fix?!

edit: maybe I found a fix:
In windows go to settings, core isolation, memory integrity
and disable memory integrity.
It's 3am and I am sick so this might be wishful thinking on my side, but I think that fixed the stutter on my side, but again I am tired.

 

[Michael Krone]

Maybe check your monitor settings. I had a similar issue when I had "response time" turned up, or down. I dont remember which but turning it to default gave me that smooth look instead of the choppy, ghosting look while in "ultra" response time.

 

[Amby]

I am having the same problem... 7800XT and 13600k. Latest CSP, no sol.

Exactly has "harris" describes, if you look at the scenery or kerbs while making a turn and there is some weird stuttering going on.
It also seems to me that during watching a replay the stutter is not in effect.

I tried everything: Vsync ingame on/off vsync driver on/off, frame limiter via driver/content manager/RivaTunrStatistics server or unlimited fps.

Turned off freesync, Turned off all video setrtings and more.

My rig could run 300 fps in hotlap mode but the problem remains even then no matter what.

A little workaround for this problem is to enable motion blur. The stuttering is still there but not as visible because everything is blurrred a bit.

Does anyone know a real fix?!

edit: maybe I found a fix:
In windows go to settings, core isolation, memory integrity
and disable memory integrity.
It's 3am and I am sick so this might be wishful thinking on my side, but I think that fixed the stutter on my side, but again I am tired.

Mate... same problem here for a few months now. When you drive through corners and look at the curbs or cars in front of you they have a light but visible stutter. I did't have core isolation enabled so none of these settings. Disabling following makes FPS a bit more stable, but this annoying micro stuttering (even at 120 fps+) is still existant.

I did a clean new installation of AC with latest CSP and Pure a few days ago. I disabled all Extensions.... still the same.

I'm on a Ryzen 5800X3D and a 4080 Phantom GS

 

[IMEAN]

Mate... same problem here for a few months now. When you drive through corners and look at the curbs or cars in front of you they have a light but visible stutter.

I'm on a Ryzen 5800X3D and a 4080 Phantom GS

Yeah you got it too. I did not mention that it is visible on cars too but that and the kerbs is where you see it!
Very weird that you have an AMD Cpu and a nvidia video card, while I have the opposite and we still have the same issues..... I had a nvidia card before (1060) and did not reinstall windows after changing cards, only uninstalled the video driver.
Did you do the same? Are we plagued by leftover drivers? Or did you clean install your system?


But I got some progress with 3 changes:

It seems that RAM plays a decisive role in these problems in AC.
If you have fast RAM snf you are using Gear1 change it to Gear2. Gear2 might be a bit slower but causes less Problems.
If you are using xmp memory profile for your RAM (you probably are) disable it for a test and see if it improves the situation.

In my testings I of course disabled all apps once. But today I used the render stats app in AC and it showed me visible spikes produced by the app actpi. This is an app that is needed for telemtry recording and it is running in the background even when disabled in the APP sidemenu.
Turning it off reduced the spikes shown in the framegraph.

Next thing is that it seems that riva tuner statistics server does produce some uneven framerates. (app for limiting framerate) So I switched to using the game frame limiter.

Did you already try the following: disable csp, disable SOL, turn down all video settings in ac and use no filter. If the problem is still there you at least know it is none of those settings that are causing it.

 

[Amby]

Oh boy... what a night. That thing drives me crazy. Thanks for your tip but it wasn't the right solution for me. But I found it... in my case... finally after felt like a decade... Try to uncheck "Extrapolate car state properly"

Never played AC that smooth...

 

[Captain Beardface]

Oh boy... what a night. That thing drives me crazy. Thanks for your tip but it wasn't the right solution for me. But I found it... in my case... finally after felt like a decade... Try it:

View attachment 727294

Never played AC that smooth...

Which of these settings are you trying to indicate here?

 

[Amby]

Which of these settings are you trying to indicate here

Sorry.... Unchecking "Extrapolate car state properly" starts the magic in my case.

 

[Vintagedriver01]

Thanks for warning for another adjustment in the future CM, ( I’m running 1.79 btw,) that can cause problems.

 

[thiago_x3m]

Guys, this has bothered me since forever (I've been playing in VR since the Oculus Rift DK1 which was 75Hz up until now with the Quest 3 that can do 72Hz, 80Hz, 90Hz or 120Hz).

All refresh rates above (and also 60Hz) will invariably cause some physics-related micro-judder due to the way the game engine calculates the car position and orientation:

According to this explanation from the Devs (

) , the Physics Engine runs at 3ms (1000/3 = 333.333.Hz). The problem arises due to this not being properly divisible by any common refresh rate, so we are always getting some frames where we get a different amount of physics steps than the other frames.

For example, at 80Hz this manifests as a 13.3333Hz micro-judder (e.g. one frame every 75 miliseconds has a different number of physics steps on it).

This is only noticeable if the camera is "glued" to the car. if you use Free Cam for example, the camera position is independent of the physics engine and therefore you get 100% smooth perfectly-frame-paced motion.

I am tinkering with a NeckFX script that decouples the camera from the car, so that it can compensate for those micro-judders by following an exponentional-average smoothed version of the car position and orientation.

vr-stabilize_expfilter.zip

drive.google.com

Give it a try and see if it helps at all. You might need to tinker with the filter values but I found that 90% for Position and 10% for direction gave me really good results. You can check the difference by going to any other "fixed-to-car" camera and then back to normal cockpit camera.

 

[Neilski]

script that decouples the camera from the car, so that it can compensate for those micro-judders by following an exponentional-average smoothed version of the car position and orientation

That's a very interesting idea.

I'm wondering though if it only works well if the view you're using doesn't show any of the cockpit?
To clarify my question:
If the view is decoupled from the car and moves smoothly in real space (when the car itself does NOT move smoothly/uniformly), then that should surely mean that the driver's view of things outside the car will move in a beautifully smooth fashion, but that the cockpit (wheel, dashboard etc.) will be jumping around from frame to frame. That sounds far more awful than trees and crash barriers moving non-uniformly though, so I expect that I've misunderstood you.

 

[thiago_x3m]

That's a very interesting idea.

I'm wondering though if it only works well if the view you're using doesn't show any of the cockpit?
To clarify my question:
If the view is decoupled from the car and moves smoothly in real space (when the car itself does NOT move smoothly/uniformly), then that should surely mean that the driver's view of things outside the car will move in a beautifully smooth fashion, but that the cockpit (wheel, dashboard etc.) will be jumping around from frame to frame. That sounds far more awful than trees and crash barriers moving non-uniformly though, so I expect that I've misunderstood you.

you understood correctly. With this script, the camera will not be glued to the car so the cockpit will move around a little bit relative to the camera in order to keep the rest of the world moving smoothly. However since the car is so close to you, these judders are only a few in-game milimeters, whereas when a tree or crash barrier is juddering in the distance it will be multiple meters at a time (much more distracting, especially since we drive looking at the distance 90% of the time anyway)

Keep in mind that if you have a display with Variable Refresh Rate (G-Sync or FreeSync) you can skip all of that and just set the in-game FPS limiter to give you frametimes which are multiples of 3ms, like 166.66Hz, 111.11Hz or 83.33Hz). Then all your frames will perfectly match the physics updates and everything shall be super smooth.

 

[Neilski]

if you have a display with Variable Refresh Rate (G-Sync or FreeSync) you can skip all of that

Yup, my next monitor will have that, without question...

you understood correctly. With this script, the camera will not be glued to the car so the cockpit will move around a little bit relative to the camera in order to keep the rest of the world moving smoothly. However since the car is so close to you, these judders are only a few in-game milimeters, whereas when a tree or crash barrier is juddering in the distance it will be multiple meters at a time (much more distracting, especially since we drive looking at the distance 90% of the time anyway)

Hmm, maybe it's more about angular rotation rather than translation, then? At say 50 m/s, stuff moves 75 mm in 1.5 ms. That's not very noticeable for a tree 50 metres away, but extremely noticeable for a steering wheel 50 cm away
However, if it's the rotation of the car that's providing the noticeable non-uniformity in the movement of scenery across the screen, I can see how that would make the far-away stuff much more important in relative terms. I still can't work out why it would be more important than the stuff close to the driver's face, because an angular increment will move everything the same amount across the screen, no?
(NB: yawing of the car wouldn't normally move the cockpit across the screen of course, but if you have a camera that yaws based on something other than what the physics engine delivers, you'd then have the cockpit moving left/right on the screen as a result. So you'd be choosing between static cockpit on screen + trees/etc juddering a little as they move across the screen, vs. trees/etc moving smoothly but the cockpit moving around instead.)

Ultimately though, the proof of the pudding will be in how it looks in screen and I imagine that you must already have observed good results with your approach? (If it were possible to make a short video with a comparison, that would be awesome.)

 

[thiago_x3m]

So you'd be choosing between static cockpit on screen + trees/etc juddering a little as they move across the screen, vs. trees/etc moving smoothly but the cockpit moving around instead.)

Exactly!
The filter works for both movement and direction, but I think that direction (e.g. yaw/rotation) is much more important due to what you just mentioned: trees are panning around the screen at many more pixels per frame during a turn than things that are moving towards you in the straights (unless you play in VR and look out of the driver's window for example).

So with my proposed settings in a flat screen I can see that the steering wheel diverges from dead center by about 2 or 3 degrees during turns, but it's really subtle and you can only see it if you're looking for it. I can definitely not see the dashboard going forwards and back due to translation since I think the corrections are super tiny.

I have yet to try it out for real in VR though (hopefully tonight) so I will keep you updated on how it goes, especially regarding the feeling of being lagging behind the real car position since the camera will be following the smoothed-out filtered path which will be a little behind the physics.

 

[thiago_x3m]

Ok so I did some extensive testing last night and had a rollercoaster of an experiance, but it all turned out great in the end.

I started out by setting the Position filter to 80% and Direction filter to 20%, and immediately noticed that the world was moving super smoothly both in the straights and corners, but the car was juddering back-and-forth horrendously in the straights. It was completely distracting and unplayable, despite the total butter-smoothness of the world around me.

That was basically the end of the road then: I would have to choose between light judderin the world movement or heavy judder in the car itself.. Then I realized I had just turned "Extrapolate car state properly" OFF according to the recommendation above. So I tried it again with "Extrapolate car state properly" ON.

The results were magnificent. I had never seen AC look so smooth in my whole life. I think what "Extrapolate car state properly" does is basically the same as my position filter, since there was no more judder relative to the car or the world with the setting back on. However, the big difference lies in the direction filtering. There is definitely no direction filtering related to "Extrapolate car state properly", which I could assert from going back and forth from Cockpit Cam to any other cam glued to the car. Cockpit Cam was 100% smooth in corners while the other cameras still present the judder at 90Hz.

Therefore my conclusion is that I don't need the Position filter from my script (just set the filter value to 100% to disable it), just the Direction filter with a value of around 15% to 20%. I just played in Magione and other tracks with long, tight corners and could tell that it's smooth like never before.

I feel that I can finally start to enjoy the game itsfelf rather than get distracted and annoyed by the judder.