AC: Stuttering reduction

Rick Malm · Jun 8, 2014

What can a user do to reduce or eliminate stuttering even in practice runs where their are no other cars on the track?

With Lotus F1 on Monza track I sometimes get as many as 6 stutters per lap, sometimes its 0 which is great.

What is the key cause of stuttering when running AC local vs MP which involves network response time as well as AC MP implementation?

Background:

My system: CPU: Intel i7-4770K Haswell 3.5GHz (some small amount overclocking was installed from Main Performance)
Video: NVIDIA | EVGA GeForce GTX 780Ti to 3 ASUS VE278Q 27” monitors 85hz refresh

I use a SSD memory for the AC install (The SSD is my C: drive)
My cpu usage is about 26% when AC is running. Processor Affinity shows all checked (0 to 8), Priority=Normal,
window resource monitor shows the cpus are getting used and none are any where near 100%, more like 40-50% and there are graphics showing PARKED cpus.

I turned off the car interior controllable items: no wheel, no driver arms.
I set Frame Limit to match my monitor max at 85.
FRAPS shows FPS will dip to 67 in some corners.
I tried reducing smoke generation and mirror resolution, I turned blur off completely.
I have not turn off HDR yet.
I have not tried to us msconfig and kill all background processes. I typically have firefox running in the background
which is the larger memory user (then Spyhunter4, explorer, LCore, office.bin, Steam....)
I have not tried to ALT-TAB out of AC when I see stuttering to see what is running with the resource monitor.
After I ran the resource monitor and looked at the CPU tab and saw a number of PARKED cpus I downloaded and ran a disable parking utility (edits the registry). This seems to have helped. Any problem with doing this?

http://coderbag.com/Programming-C/CPU-core-parking-manager

http://www.coderbag.com/Programming-C/Disable-CPU-Core-Parking-Utility

AC settings: Fullscreen Rendering ON | Triple Screen ON (6065x1080) | Vsync - OFF | Frame Limit - 85 | Aniso x 8 | AA x 4 | FXAA x 3 | Shadows -Low | World Detail - Maximum | HDR Color Sat On @ 92%| Smoke Generation – Low||Smoke in Mirrors OFF| Motion Blur - OFF | Mirror Resolution High| CubeMaps at Low | Faces per Frame - 4

Rick Malm · Jun 14, 2014

Dont worry about it. 1st I have figure out how
to get the IR mouse to work in the BIOS
with the mouse IR receiver plugged in USB2 or USB3.
I can get to the advanced panel but then can not get to the
tabs along the top and I assume they are mouse selectable or maybe tab.

I just found my Asus Z87 manual and I see the option on pshr 2-8

I need to learn how to move around here in the BIOS. Learning!!!

cerebus23 · Jun 14, 2014

Arrow keys and tab usually works or a combo of the two.

Rick Malm · Jun 14, 2014

Blkout,
Ok did it. Worse. 13 stutters in 5 laps (but stutters are short).
No time to try HIGH prty.

Blkout · Jun 14, 2014

Rick, I'm out of suggestions at this point. I'm really bummed by that too because the problem still isn't resolved. Are you using the latest Nvidia drivers, 337.xx?

Joao Alves · Jun 15, 2014

Blkout said:
Can anyone else here confirm they're running an i7 CPU with hyperthreading enabled and not getting stuttering?

I'm running an i7 4820K with hyperthreading on at 4.6 GHz normally, but down to 4.0 now in the Summer. With either one of the speeds, I get no stutters whatsoever. Unfortunately I can't provide much insight as to why, since I only turned on in game vsync.

Rick Malm · Jun 15, 2014

Yes, Nvidia Driver latest 337.88
Bummer... No total solution to never have some shutters.

Just doubled check hyperthread=disable race 17 and 18 and got
18 stutters in 5 laps and with prty high got only a few legs 16/5laps. Guess I moved game back to my SSD C: drive.

Thanks to all of you for trying, I learned alot.

Getting tired of this track but I wanted to make the tests always the same.

I did run GSCE again today only 1 stutter, so maybe the next release of AC will be better.

I decided to post a summary of settings after trying all the suggestions in this thread trying to trade off image quality vs the removal of stutters.
If a setting did not have a noticeable effect on stuttering, I moved it higher to get a better image. I have a few races with 0 stutters but average is at least 2 per lap.

AC in game settings

Resolution: 6060x1080
Rendering Mode: Triple screen
Fullscreen Rendering: checked
Vertical Sync: checked
Framerate limit: 85fps
Anisotropic Filtering: 8x
Anti-Aliasing Samples: 4x
Fast Approximate Anti-Aliasing:off
Shadow Resolution: low
Disable HDR: unchecked
Motion Blur: off
Color saturation: 92%
World detail: Max
Smoke generation: normal
Show smoke in mirrors: off
Field of View: 51°
Glancing left/right speed: max
G-force effects: all 1
Camera shake at high speed:0
Display time gap: checked
Lock onboard camera to horizon:checked
Hid driver arms: checked
Lock virtual wheel: checked
Virtual steering wheel rotation limit: off
Hide driver arms: checked
Hide virtual steering wheel: checked
Mirror Resolution: High
High Quality Mirror Reflection: checked
Cubemap Resolution: Low
Faces per Frame: 1

AC file settings in Steam

C:\Program Files (x86)\Steam\SteamApps\common\assettocorsa\system\cfg\dx11 MAXIMUM_FRAME_LATENCY=1

Nvidia Control panel settings

Ambient Occlusion: off (not supported for AC)
Anisotropic Filtering: 16x
Antialiasing – FXAA (not supported for AC)
Antialiasing - Gamma Correction: on
Antialiasing - Mode: off
Antialiasing - Transparency: Multisample
CUDA - GPUs: All
Maximum Pre-Rendered Frames: 1
Multi-display/Mixed-GPU Acceleration: Multi display performance mode
Power management mode: maximum performance
Shader cache: on
Texture Filtering - Anisotropic Sample Optimization: on (tweakguide recommends on for performance)
Texture Filtering - Negative LOD Bias: Clamp (tweakguide recommends Clamp)
Texture Filtering - Trilinear Optimization: On (tweakguide recommends On)
Threaded Optimization: Auto (tweakguide recommends Auto)
Triple Buffering: On (tweakguide recommends On if Vsync On but I only have in game Vsync On and I think Nvida setting of Vsync off overides the In game Vsync On)
Vertical Sync: off (off results little fewer stutters. Tweakguide recommends which is Use the 3d Application setting and in game to ON but if I set Nvidia Off allows me to get 85fps and fewer stutter where as Nvideo vsync “Use in game” its held down to 60 get a few more stutters per lap.

Computer

CPU: Intel i7-4770K Haswell 3.5GHz (not overclocked yet, plan to test at 4GHz)
Video: NVIDIA | EVGA GeForce GTX 780Ti with latest driver version 337.88
3 ASUS VE278Q 27” monitors that have 5hz refresh
Hyperthreading: Enabled (disable did not help)
Cpus unparked (this did help)
Set 3 AC processes to priority HIGH in taskmanager (sometimes helped)

Other items tested

Moving Steam and apps to non SSD disk and did see 2x improvement but stutters were much larger.
Hyperthreading disabled and got 10x worst stuttering
Turn all AC settings to low vs max: not much difference, this was very unexpected.
Set 3 AC processes to priority HIGH in taskmanager (maybe improvement but not clear)
Used msconfig and removed as many background processes as possible. This seems to help some.
Uninstalled Norton 360, using Kaspersky. (maybe helped)
Uninstalled Spyhunter and RegHunter and installed Malwarebytes and manually run Malwarebytes to avoid scheduler running.

Blkout · Jun 15, 2014

Rick, can you try setting all AC graphics settings to their lowest except the resolution. Also enable Vsync but limit fps to 60fps. Tell me what that does.

Rick Malm · Jun 15, 2014

I did this once before and was not expecting what happened.
But per your request I just did it Race 20 19 stutters in 5 laps 85fps limit and Race 21 60fps limit with 21 shutters . I have changed the msgconfig to normal startup so you see a few more background processes. I did not set priorty to high. Nvidia settings vsync set to match application.

cerebus23 · Jun 15, 2014

The old theory was that the physics engine and the graphics got desynched and caused some of the studdering and hitching. The old way was rendering the fps at values like 59, 119 and locking the fps.

Dunno if that still holds or is correct at all but something about the game causes hitches, I still run my fps frame limited to 59 and yea maybe once or twice a lap i get Bit of a hitch but there were older builds of the game that were far far worse.

Remember silverstone that back section in the S back there in the earlier builds i would hitch about the start of the S section and then the car would synch a bit down the road a half second or so later teleporting me down the track.

I am reasonably sure its the game itself, most of us just ignore it, especially since its tiny compared to the older stuff. I really hope they fix the issue for 1.0 and eagerly await the gfx update this week to see what that does.

Rick Malm · Jun 15, 2014

Cerebus23, tks I will try this later today.
Yes I driven the track so many times I know when the hitch is coming and I can almost ignore them now.
Still bugs me.

cerebus23 · Jun 15, 2014

We wait for friday with fingers crossed i would love to see the hitches and etc gone.

Blkout · Jun 15, 2014

Nothing honestly makes sense at this point. By lowering the graphic detail, you have eliminated any graphic bottlenecks. By changing hard drives, you have eliminated any storage device issues. By disabling hyperthreading, unparking cores, setting affinity, you have eliminated any CPU bottlenecks. By enabling, disabling V-sync, capping frames, you have eliminated any display issues. Yet the problem still remains...

Rick Malm · Jun 15, 2014

cerebus23 said:
The old theory was that the physics engine and the graphics got desynched and caused some of the studdering and hitching. The old way was rendering the fps at values like 59, 119 and locking the fps.

Tried FPS=59 No help, still got about 16 per 5 laps, some were longer than before.

Blkout, There was some progress. Looking back at saved screen file names and thread comments I see that
I started with about 20 stutters per 5 lap race, this was terrible..

Your advice and others help me get some down to few with 2 or 0 but they results were not consistent or repeatable.

Now I have some higher resolution settings as time went on, at some point I wanted smoke on as well as
better line AA. I wish I would have captured all the settings for each test. I would try something, make some
changes and if it was not dramatic I would move it back to get more image detail and move on to the next setting.
As I look back I only have the tread notes to guess what I had done.

Before I started counting the test by race number, I reported setting trying some ones suggestion
Latency to 1 and in game vsync on got me to 0 stutters and I though the problem was solved. Tuesday at 09:53 but after lunch with no change it went back to 2 stutters per lap.

Race 7, Later I haf 2 races no stutter right after OS rebuild, I did not capture taskmanager in the image. race 6,7 (image of 6 show some)
Race 11 only 2 stutters pre-rendered frames to 1 and setting Priority=High
Race 13 ac Prtry= high, about 4 stutters in 3 laps
Race 14 3 stutters from D: install was an improvement in count but they were longer hitches
Race 15 Steam moved to D: did whelp with Priority on the 3 AC set to HIGH = 0 stutter
I could not get simvibe working on D: so I move steam back to C:
Race 19 on 2 stutters with prty HIGH again.

So I have lots of options to try to go back and see if I can get to near 0. Maybe I should do testing in practice and remove the load of other cars on the track to try to get more consistent result.

Rick Malm · Jun 15, 2014

Just to test and idea, I decided to try adaptive vsync and fps=59 Race 25 and got 16 stutters then with no setting change I did a 5 lap practice run:1 stutter. Clearly the load of doing the graphics for the other cars costs. In the race tests I was not in the pack but most of the time I could see them from several car lengths away to all 9 of them out of sight. Doing testing with other cars can never be consistent but just Practice might not show the issue and allow one to optimize settings. I just ran 2 practice runs with max setting 1/2 size stutter and min in game settings got 3.5 stutters with fps max at 85, adaptive vsync. You can see the Max settings put GPU at 100% and fps around 50 but min settings GPU is only around 35% and fps at 85 and got some stutters. Stutters on min settings unexpected. Observation. The min settings make the road image as smooth as butter. Max settings the movement of the road clearly is happening and is not smooth.

At this point I am waiting for a new AC release.

Blkout · Jun 15, 2014

Rick Malm said:
Tried FPS=59 No help, still got about 16 per 5 laps, some were longer than before.

Blkout, There was some progress. Looking back at saved screen file names and thread comments I see that
I started with about 20 stutters per 5 lap race, this was terrible..

Your advice and others help me get some down to few with 2 or 0 but they results were not consistent or repeatable.

Now I have some higher resolution settings as time went on, at some point I wanted smoke on as well as
better line AA. I wish I would have captured all the settings for each test. I would try something, make some
changes and if it was not dramatic I would move it back to get more image detail and move on to the next setting.
As I look back I only have the tread notes to guess what I had done.

Before I started counting the test by race number, I reported setting trying some ones suggestion
Latency to 1 and in game vsync on got me to 0 stutters and I though the problem was solved. Tuesday at 09:53 but after lunch with no change it went back to 2 stutters per lap.

Race 7, Later I haf 2 races no stutter right after OS rebuild, I did not capture taskmanager in the image. race 6,7 (image of 6 show some)
Race 11 only 2 stutters pre-rendered frames to 1 and setting Priority=High
Race 13 ac Prtry= high, about 4 stutters in 3 laps
Race 14 3 stutters from D: install was an improvement in count but they were longer hitches
Race 15 Steam moved to D: did whelp with Priority on the 3 AC set to HIGH = 0 stutter
I could not get simvibe working on D: so I move steam back to C:
Race 19 on 2 stutters with prty HIGH again.

So I have lots of options to try to go back and see if I can get to near 0. Maybe I should do testing in practice and remove the load of other cars on the track to try to get more consistent result.

Rick, is it just one track that you have this issue? Is it Monza or Monza 66 or both? I think I read that it happens alone as well as with AI. Also, I believe your resolution should be 5760x1080, not 6060x1080 correct?

Blkout · Jun 15, 2014

You clearly love this game though for doing all of this testing and documenting.

Rick Malm · Jun 15, 2014

I only used one track for the testing. Monza 1966 to get high track speeds and number to compare. I could try another track if you would like. The 6060 width res is due to bezel correction of the triple monitor. It shows up as 6060x1080 in AC and in Nvidia as corrected resolution. Yes it looks like the AI is the load that puts one over the threshold of 0 to a few stutters per 5 laps, and AI load and pushed it up to several per lap or 10-18 stutters / 5 laps.
Yes I really enjoy the game, getting to a point that I need the Racedepartment driver training, I have hit my lap limit at 1:15.3sec in the mod lotus 125 s1 that the Gabor Bernhardt posted on RSR live at 1:11sec. I am using his car mods as well.