Super frustrating CPU 99 Occupancy HELP PLEASE

[Hugo Becerra]

I have been experiencing an issue with AC, it started around the time I downloaded and installed CSP .1.75, but since then it happens with every csp build.
Problem is the CPU Occupancy 99% and stuttering (it kind of goes into slow motion, I dont know if stuttering is the right word).
I tried updating SOL 2,1, updating GPU controllers, verifying game integrity, and nothing works
My PC build has been the same siince the start of the year and it has run everything with no problem (A lot of AI, heavy mods, rainfx, etc) Content manager sometimes crashes and makes a report when starting a session, sometimes it does not.

Ive tried every fix that I can find (wheel ffb, face reflections down to 1, low graphics, etc )and havent seen a solution yet, any idea ?


MY PC BUILD

NVIDIA Geforce RTX 2060 SUPER (controller 466.27)
INTEL CORE I7-9700F
31.93 GB RAM


FIXED by using CPU PROCESS LASSO AND FORCING A MULTI-THREADED USE

 

[pattikins]

As I didnt notice ANY downside of enabling this mod I obviously didnt do any testing on this so cant give you raw data, was simply referring to "imagine would trouble an Intel 12900K cpu" statement saying that "I dont think it would", based on my experience and my much less powerfull CPU.

I agree with your view up to a certain point, that is, taken in isolation, with stock AC content, the 12900K would probably churn out 80fps without any noticeable dropped frames using the 'Virtual Mirror' mod. I do, however, feel that the 12900K wouldn't be on such firm ground if one was to throw in CSP, SOL, 20 modded cars/track of unknown quality, and a whole bunch of mods:

INFO | Extension `Rain FX` enabled, settings loaded
INFO | Extension `Windscreen FX` enabled, settings loaded
INFO | Extension `Graphics Adjustments` enabled, settings loaded
INFO | Extension `New Behaviour` enabled, settings loaded
INFO | Extension `Car Instruments` enabled, settings loaded
INFO | Extension `Smart Mirror` enabled, settings loaded
INFO | Extension `Reflections FX` enabled, settings loaded
INFO | Extension `Particles FX` enabled, settings loaded
INFO | Extension `Fake Shadows FX` enabled, settings loaded
INFO | Extension `Grass FX` enabled, settings loaded
INFO | Extension `Brakedisc FX` enabled, settings loaded
INFO | Extension `Shadowed Wheels` enabled, settings loaded
INFO | Extension `Skidmarks FX` enabled, settings loaded
INFO | Extension `Colorful Shadowing` enabled, settings loaded
& then there is the high in game graphics settings.

 

[RasmusP]

I agree with your view up to a certain point, that is, taken in isolation, with stock AC content, the 12900K would probably churn out 80fps without any noticeable dropped frames using the 'Virtual Mirror' mod. I do, however, feel that the 12900K wouldn't be on such firm ground if one was to throw in CSP, SOL, 20 modded cars/track of unknown quality, and a whole bunch of mods:

INFO | Extension `Rain FX` enabled, settings loaded
INFO | Extension `Windscreen FX` enabled, settings loaded
INFO | Extension `Graphics Adjustments` enabled, settings loaded
INFO | Extension `New Behaviour` enabled, settings loaded
INFO | Extension `Car Instruments` enabled, settings loaded
INFO | Extension `Smart Mirror` enabled, settings loaded
INFO | Extension `Reflections FX` enabled, settings loaded
INFO | Extension `Particles FX` enabled, settings loaded
INFO | Extension `Fake Shadows FX` enabled, settings loaded
INFO | Extension `Grass FX` enabled, settings loaded
INFO | Extension `Brakedisc FX` enabled, settings loaded
INFO | Extension `Shadowed Wheels` enabled, settings loaded
INFO | Extension `Skidmarks FX` enabled, settings loaded
INFO | Extension `Colorful Shadowing` enabled, settings loaded
& then there is the high in game graphics settings.

To be fair though, only rain fx and particles fx should really cause additional load for the cpu.
Graphics adjustments, car instruments and smart mirrors highly depend on what's set in there specifically.
It's quite bizarre that in that video, the main_t is so low whole phy_late is counting up steadily!

For my system, cpu bottlenecked fps and main_t go hand in hand while phy_late always stays below 10 for a single lap. Mostly at 0!

 

[pattikins]

To be fair though, only rain fx and particles fx should really cause additional load for the cpu.
Graphics adjustments, car instruments and smart mirrors highly depend on what's set in there specifically.
It's quite bizarre that in that video, the main_t is so low whole phy_late is counting up steadily!

For my system, cpu bottlenecked fps and main_t go hand in hand while phy_late always stays below 10 for a single lap. Mostly at 0!

I was also aware that rain fx could have an impact on cpu performance, but I don't know much about the others with the exception of the smart mirrors video that I watched a few years back. As someone who has been through the slo-mo experience in VR, hitting that magic number of fps is more important than any aesthetic experience, and as such, any additional mods have to be carefully weighed against that goal.

 

[RasmusP]

I was also aware that rain fx could have an impact on cpu performance, but I don't know much about the others with the exception of the smart mirrors video that I watched a few years back. As someone who has been through the slo-mo experience in VR, hitting that magic number of fps is more important than any aesthetic experience, and as such, any additional mods have to be carefully weighed against that goal.

Absolutely!
Best advice would be to disable csp completely and run some stock content.
Mod content can cause many different issues. Same for apps that might be badly coded.

 

[A man with a Harmonica]

Just to leave here my recent experiments on the subject. Unfortunately I can't add anything to the online server part.

In my experience 99% processor occupancy occurrences is always from AI cars piling up in any part of the circuit. The problem is more frequent when the grid is sorted with a large variety of cars.

Some mod tracks with bad physical 3d mesh (more than one physical object overlapping vertices etc) don't help as well as require the game engine to clean up the mess before do the calculations. The probe to calculate the tyre physics will have to sort out the points underneath to decide what to do.

In the case of Monaco and other narrow street circuits some AI cars don't have enough steering angle to get around some specific corners coming from a non usual race line (off the fast_lane.ini) which happens a lot when they're fighting for positions. Then the AI car end up stuck (the code doesn't deal with the reverse gear) and eating cycles of the physics engine to deal with the incident. If another AI stuck at the same position the contact between them starts a snowball effect and can lead to a 99% ocuppancy.

A good left, right and fast lane AI track lines to inhibit the bots trying insane overtakes and edited ai.ini / car.ini files to give them a better brake_hint and steering angles will prevent 99% of the AI havocs and CPU bottleneck. If a car completely block the road you can be sure that you will have a 99% GPU disaster.

In other words, if you want to have a good offline race against the bots be prepared to learn how to create a good AI for the tracks and create specific car tunes for a non usual track like Monaco or Macau. Assetto Corsa Car Tuner is a good tool for it since it allows you to create a version of the car only for bots and leave your default car intact to avoid online mismatches.

IMHO Asseto Corsa developers made a questionable design concept when decided to assign the same player physics to the AI cars. It's a waste of CPU resources to calculate detailed physics for a AI bot car running in the other side of the track. The RF2 solution seems to be more reasonable on this subject.

 

[Vintagedriver01]

You could, use the alternative AI mods for the track. If an circuit does have AI difficulties like Longford, there is mostly an AI mod.
like this 2 for Monaco ‘66 https://www.racedepartment.com/threads/ai-for-monaco-1966.194882/
https://www.racedepartment.com/threads/ai-fix-monaco-1966.176586/

 

[Shadow420]

Hi everyone i got same problem, my pc: E5 2667v2, RTX 3070, 24g ddr1866 mem, ac is on a sata 3 ssd, 4k
Any advice or tips for me? I make a screenshot of performance monitors, task manager and hw monitor.
I hope you will see everything that is on the screenshot, I didn't cut it the best.
So far I've tried all the possible solutions I've found. FFB I tried all combinations.
Windows are optimized, all settings from bios to the system itself are optimized properly.

 

[RasmusP]

Hi everyone i got same problem, my pc: E5 2667v2, RTX 3070, 24g ddr1866 mem, ac is on a sata 3 ssd, 4k
Any advice or tips for me? I make a screenshot of performance monitors, task manager and hw monitor.
I hope you will see everything that is on the screenshot, I didn't cut it the best.
So far I've tried all the possible solutions I've found. FFB I tried all combinations.
Windows are optimized, all settings from bios to the system itself are optimized properly.

Your cpu doesn't have the best single core performance so you won't see great fps, depending on your graphics / csp settings and session settings.
It just has plenty of cores for multithreaded applications. Sadly AC only really uses 2 cores.
The loads in Taskmanager or hwinfo etc don't show single core limits.
They average 1s, which means 3.500.000.000 cpu cycles at 3.5 GHz averaged.
Windows shuffles the load around from core to core, so the 1s average shows load on most cores.

Anyway, to find a solution:
Your csp render stats are the best clue that you've got.
UI for cpu frame time and final image for gpu frame time look very high.
Dive deeper into these and disable the apps that cause the UI load.

And probably some fancy graphics settings are causing the GPU frame time.

Also the mirrors seem a bit high. Are you using the real mirrors extension in csp? And do you need it?

Every ms you can save means some fps! Frame time of 19 ms = 52.6 fps.
18 ms =55.5 and 17 ms = 59 fps.

 

[Shadow420]

Your cpu doesn't have the best single core performance so you won't see great fps, depending on your graphics / csp settings and session settings...

My graphics settings are on SS. My mirrors are on max settings, I don't use any mods for them. Honestly, on 4K or 2K or 1080p when I try with these same settings, I always have the same problem. My graphics are 100% loaded (Pure 0.148 + Skydome + AC Aura Photo) Also at 1080p I have 60 locked FPS with 3070 and a friend with the same card only with a weaker rest of the conf at the same settings 80 to 90 fps. Of course, my friend, the game correctly shows the processor load.

EDIT
I add a ss from mirrors settings.

EDIT2
I add 3 ss from CSP Render stats.

 

[RasmusP]

My graphics settings are on SS. My mirrors are on max settings, I don't use any mods for them. Honestly, on 4K or 2K or 1080p when I try with these same settings, I always have the same problem. My graphics are 100% loaded (Pure 0.148 + Skydome + AC Aura Photo) Also at 1080p I have 60 locked FPS with 3070 and a friend with the same card only with a weaker rest of the conf at the same settings 80 to 90 fps. Of course, my friend, the game correctly shows the processor load.

EDIT
I add a ss from mirrors settings.

EDIT2
I add 3 ss from CSP Render stats.

Thanks for the Screenshots!
Sadly you extended a lot that barely shows any ms impact but didn't show a few things with higher ms numbers like the UI parts to see which apps are causing the quite high ms.
You did include the python stuff though.
The need for speed UI is taking quite a lot. If you can, try to use a different HUD app.
I know the need for speed one looks awesome but it takes 1.47 ms alone.

If you'd disable only that, your fps would go up by 3-5 fps.

The other big parts I can spot are:
- reflections: you put them to 6 faces per frame. They are very cpu intensive and the reflections FX from csp implemented some "fake smoothing" so you can set them to 1 or 2 and still get smooth reflections. Definitely set them to 1 and test the visual quality. If it's not good enough, set it to 2 faces per frame.

- smart mirrors: it's not THAT heavy, but I would disable them.. Do you really need them?

- SSLR reflections from the extra FX extension. Yeah, they are pretty cool but they do have a big performance impact...

- what I've never seen yet is the AABB stuff. What are your extra FX ambient occlusion settings? Is that the Intel one?

Of course, my friend, the game correctly shows the processor load.

No it doesn't. There's currently no way to see single core limits without being a Windows Developer and even then I'm not sure..

The only indicators we have:
- If the graphics card is at 95% or more, the graphics card is the limitation

- if the overall cpu load is at 100%, the multithread performance of the cpu is the limitation

- if the cpu and the gpu aren't close to 100%, you have two possibilities:
1. Single core limit of the cpu
2. An fps limiter is active (vsync, fps limit, game engine limit etc)

In your first screenshot, your cpu is at 19.xx ms and your gpu at 20.xx ms.
So the graphics card was limiting there and probably showed 100%?

However if you'd reduce the gpu load, your cpu would limit at 19ms frame time, which only results in 53 fps, instead of the 50 fps at 20ms frame time (1000ms/20ms = 50 fps)

Also at 1080p I have 60 locked FPS with 3070 and a friend with the same card only with a weaker rest of the conf at the same settings 80 to 90 fps.

In your content manager settings I see you're using the fps limiter set to 50 fps.
And you also have vsync activated with your monitor stating to be 60 Hz.

So with the limiter you're locked to 50 fps, without the limiter vsync locks the game at 60 fps.

 

[Shadow420]

Thank you my friend for your help! I just changed from 6 to 2 faces per frame Turned off the smart mirror, so I'll test it. I would beg you to tell me exactly what to screenshot. I am adding a couple of screenshots of my settings.

EDIT
Yes that is intel. I have been using xeons for desktop, gaming and workstation for 10+ years. As the years go by, I switch the mbo and cpu from the workstation to the gaming PC. Because so far xeons have proven to be excellent for gaming. Of all the games, I only have a problem with the processor in Assetto Corsa. For example, in Battlefield 2042, my processor maxes out at 60% on High settings at 4K resolution.

EDIT2

Now the game runs at 60 fps, but it's slow motion, I don't know how to say it. It looks like it's fluid but everything is very slow.

 

[RasmusP]

Can you do the same csp render stats screenshot with 1080p, fps limiter off (or raised to 100 or so) and also vsync disabled?

Would be interesting to see how the frame times change then.

What's clear though: 4k with csp, pure, simhub etc is pretty heavy on the hardware. It's an "old" game but with all the additional stuff is easily more demanding than ACC, which is way newer.

What car and track are you using in the screenshots? Depending on their polygon, LOD and feature counts, the performance can be very different compared to a stock Kunos car on a Kunos track.

I have no idea why it should feel like slow motion though. It might be the input lag from vsync but that should've been there before.
Do the test for the render stats without vsync and without the limiter and while doing that, check if the "slow motion" feel is gone too.

It will probably stutter and show tearing, that's another topic though.

My question with the Intel was about the ambient occlusion setting in extra FX (ASSAO by Intel), sorry.
But that's disabled.

I didn't see this "AABB prep" in my render stats app, but I'll have a look when I'll get home!

Your xeon is very good for games that can use a lot of cores.
Sadly simracing only needs 4 cores but the highest single core performance you can get

Have a look here:
https://www.cpubenchmark.net/compar...-7600K-vs-Intel-i5-9600K-vs-AMD-Ryzen-5-5600X

I've added a few "budget simracing CPUs" for comparison. The xeon's multicore performance is pretty good, but the single core rating isn't great.

But we got the cpu frame time to be shorter than the gpu frame time, which is good!
The gpu frame time is still very high though...


Next:
I never used the dxgi extension since my monitor isn't hdr and I'm using fullscreen, not windowed.
But simhub overlays are only working in windowed mode (borderless).
I guess your 4k monitor is an hdr and TV?

However you have fullscreen activated in the graphics settings. So are you even using simhub overlays or how is that used?
It takes 0.60ms in the python app section of the csp render stats app.

Sorry, your settings don't really make much sense overall.
You have fullscreen + vsync checked but then set a fps limiter to 50 fps, which normally gives really bad stuttering since vsync will alternate between 30 and 60 fps.

Then you have the dxgi windowed mode optimization active, although you're using fullscreen.

Explanation for vsync with too low limiter below:
The monitor, with vsync active, always waits for a complete frame before putting it on screen.
60 Hz means 16.67ms between frames.
50 fps means 20ms between frames.
So the first frame will get displayed, then there's a 3.33ms seconds gap before the next fps is ready.
So the monitor will display the first frame a second time while waiting.
While that frame is displayed a second time, the gpu will have completed the second frame.

So as the 3rd round of the monitor, the 2nd fps will get displayed for 16.67ms.
Now the gpu had enough time to complete the next frame and will display the 3rd fps in the 4th round of the monitor.

Yes, this is quite complicated but in short:
Monitor rounds & fps:
1st round = frame/fps 1
2nd round = frame 1 again
3rd round = frame 2
4th round = frame 3
5th round = frame 3 again
6th round = frame 4
7th round = frame 5


Sorry that there's no quick help!
A quick fix would be to disable everything in csp apart from:
- General
- ffb tweaks
- grass fx
- reflections FX
- smart shadows

But it would also kill night lights/weather transitions/rain etc.

 

[RasmusP]

Here are my settings:

CSP: No pure, no weather, no lighting. Yeah, driving in the sunset or night looks awesome but cripples performance. I'd say it looks pretty good without it too! (look at the Screenshots in game later on)

Every extension that I don't Screenshot is at defaults (everything white, nothing red)!

Here is my CSP Render Stats App.
Session Settings:
- BMW Z4 GT3
- Union Island West Layout

Screenshots taken while sitting in the pits but clicked on "drive" too see the apps.

For overall looks:

Here are the 2 Render Stats Screenshots:

I have a slightly underclocked 3080. About 15% more performance than your 3070.
But only 3440x1440, however limited to 93 fps and I'm getting these.
I'd guess I you should easily get around 75 fps in 4k with a 3070 and my settings.

My CPU is an AMD 7600X, which has a bit more than 2x the Single Core Performance of your Xeon. So you can basically double all the CPU frame time parts for comparison.

One big difference, even when taking it x2 is the UI.
It's 0.48ms for me. Should be around 1.0-1.3ms for you.
But your Screenshots show 1.96ms for UI!
For some weird reason your render stats don't show the individual apps but something is using a lot of CPU there!

 

[RasmusP]

Double post since I can only attach 10 files... Here's my PP Filter.
Goes in here:
\Steam\steamapps\common\assettocorsa\system\cfg\ppfilters

It's based on the "Natural Mod". Pretty black cockpit, bright outside. I really like it

 

[Vintagedriver01]

@RasmusP why not publish your setting as an CM link, (CSP & Video settings), so he could easily load this in his CM.

 

[RasmusP]

@RasmusP why not publish your setting as an CM link, (CSP & Video settings), so he could easily load this in his CM.

Yeah I've thought about doing that but two reasons why I didn't yet:
- when he wants to compare the settings, he needs a picture of my settings instead, since CM has no a/b comparison feature

- the cm links get ** here at RD so I would need to replace the dots and he would have to copy the links and replace it back to dots

But yeah, valid question and I can do it

 

[Vintagedriver01]

https://acstuff.ru/s/test

It will not be censured I noticed

 

[RasmusP]

AC Graphics Settings:

Content Manager

acstuff.ru

CSP Settings:

Content Manager

acstuff.ru

I'm using the Patreon 0.1.80 preview though. The settings preset should work with other versions anyway, but a few settings that don't exist in earlier versions might not apply automatically