1. Do you need support for Assetto Corsa Competizione? Please use the proper forum below and ALWAYS zip and attach the WHOLE "Logs" folder in your c:\users\*youruser*\AppData\Local\AC2\Saved. The "AppData" folder is hidden by default, check "Hidden items" in your Windows view properties. If you report a crash, ALWAYS zip and attach the WHOLE "Crashes" folder in the same directory.
  2. FOR ASSETTO CORSA COMPETIZIONE: If you report issues with saved games, please always zip and attach your entire User/Documents/Assetto Corsa Competizione/Savegame folder!
  3. If your game executable is missing, please add your entire Steam directory to the exceptions in your antivirus software, then run a Steam integrity check or reinstall the game altogether.

CPU Usage Warning

Discussion in 'ACC Hardware Discussions' started by Eric D, Mar 8, 2019.

  1. Jacobs

    Jacobs Racer

    Yup. It happens (much less) in online too. Doesn't happen on empty track.

    Attached Files:

  2. BrunUK

    BrunUK Alien

    Take a look at the following screenshots. Graphics set to minimum and all but 4 cores disabled via task manager.

    All opponents visible: 80FPS


    Only 5 Opponents visible: 120fps


    In an apparently CPU-limited scenario, reducing opponent visibility has a huge effect on framerate.
    LeDude83 likes this.
  3. Lord Kunos

    Lord Kunos His master's voice. Staff Member KS Dev Team

    again, the warning has nothing to do with FPS. It's about the physics not being able to finish its calculations in time.
  4. BrunUK

    BrunUK Alien

    Right, but if opponent visibility uses significant CPU resources maybe reducing it will help with the physics processing?

    I did say 'try' for a reason.
    LeDude83 likes this.
  5. pankykapus

    pankykapus KS Dev Team Staff Member KS Dev Team

    You have almost the exact same amount of physics thread occupancy and late count in both cases, so your CPU is constantly late with calculations regardless.
    MathMilitary likes this.
  6. Arpadian

    Arpadian Racer

    Sure, beforehand i dont use wheel, using for now till mouse steering is fixed and can customize the keyboard i'm using a combination of vjoy and mousetovjoy made by R1PER ( member of this forum ) to emulate a steering wheel through the mouse ( yeah really convoluted but is the only solution to the not working MS in game )

    Now the result of testing SP with Ai
    First screenshot 10 AI + me / no cpu warning

    Second screenshot 12 AI + me / no cpu warning

    3rd screenshot , No screen
    15 AI+me / cpu warning
    couldnt catch the msg since flashes way to fast to take screenshot

    looks like 15 is the new max for me, was 10 pre build 0.6 ( that cpu optimization on the latest patch is fantastic )no stuttering or slideshow like was before, also you can see that none of the cores reach 100% usage but i bet it reach the max IPC ? ( like happens on others games like Assassins creed odyssey that uses almost 90-100 cpu usage)

    Log Attached
    Thank you for taking the time to analyze the log

    i did till got ACC and couldn't configure the controls to my liking so in rebellion i changed my signature to the one i have now, i will add the rig information on the signature
    thanks for the tip

    i know my cpu is crap and doesn't cut for IPC or heavy CPU physics calculations still in ACC playing MP i have no problem at all,

    mini offtopic, i can race on AC in spa with 24cars at 50-60fps no problem, No stuttering, no freeze, is silk smooth racing and all settings to max 1600x900 and using reshade, Shader light patch and sol weather mod.

    Attached Files:

    • AC2.zip
      File size:
      118.4 KB
    Last edited: Mar 9, 2019
  7. MakeMeLaugh

    MakeMeLaugh Simracer

    Having the same problem in multiplayer as well. It was fine monday and tuesday with 0.6, problem started after 0.6.1. I checked task manager at the moment it happened and cpu wasn't even close to 100% usage while the message was flashing at the top of the screen. Also slow downs happens sometimes but not exactly when the message flashes. Using FX8350.

    These slowdowns make absolutely no sense. They never happened in previous patches, why are they now a thing?
  8. Minolin

    Minolin Staff Member KS Dev Team

    While you are benchmarking (and fighting this), please also make sure you minimize what is running in the background, and see how big that impact is.
    Sadly nowadays even browsers with a few tabs open do add lots of noise; same for local database systems, antivir, and such things.

    If you go to the task manager/performance, you can see the number of threads currently active on your system:

    So in this moment, 3281 threads are fighting for my few cores. Sure most of them do not really do something, but that's already a bit too much (well development PC with several Visual Studios open, local databases running etc add up a lot here). But that strongly depends on your core count - i7 or i9s will ignore this, while older i5s may suffer due to overhead quite early. If I recall correctly, a clean Windows Server comes with a bit below 1k threads active, and I'd suspect any "normal" consumer windows should be below 3k. If you end up with 4, 5, 10k - it's time to think about a clean windows install (with reset), and not clicking every single program that wants to be installed ;)

    Anyways, the more important figure is how much work the complete system has to do - and if you have 50 programs open that constantly phone home, do backups, scan files, stream videos, play music etc - this may or may not push our physics/AI threads into the edge.
    mister dog likes this.
  9. BrunUK

    BrunUK Alien

    I simply disabled the opponent visibility so the late count wasn't reset. Restarting the race doesn't reset it either, you have to actually exit the session.

    I had since repeated it, driving the formation lap until the race started which produced the following...



    Occupancy is practically identical but the late count is significantly less, down to 1/3 compared to all opponents visible. What's the 'B' value, cos that doubles when oppnents aren't visible.

    Am glad I have some devs attention on this (appreciate it's a Saturday as well), because it's not just relevant to older computers. Even the latest CPUs take a battering in VR, (often meaning GPU use is nowhere near maximum). If this apparent CPU cost from having other cars visible could be reduced it may significantly boost performance. I've also made the point previously that having opponent visibility set to 'all' seriously reduces performance even when they're not being rendered - i.e. all cars are half a lap away. That doesn't make much sense to me, any chance of some optimisation there?
    LeDude83 and alex bonner like this.
  10. BrunUK

    BrunUK Alien

    @Arpadian What happens if you increase the AI amount but keep the opponent visibility lower?
  11. Arpadian

    Arpadian Racer

    got the slideshow where all the physics run at 1 frame at a time

    they also said that decreasing the OV doesn't affect the physics calculation, the cars are hidden but still the cpu need to calculate those hidden cars physics
    opponents visibility only affects the GPU load
  12. BrunUK

    BrunUK Alien

    With what settings?
  13. LeDude83

    LeDude83 Alien

    Stefano, @BrunUK has shown in the CPU Benchmark Thread that it's the rendering of AI cars that hits the CPU hard, much harder than the physics.

    When limiting the max rendered cars, the CPU usage went down massively while the AI cars still had their physics calculated.
    I reproduced this behaviour and can confirm.

    This is one of the weak spots of ACC right now IMO. The rendering of cars shouldn't hit CPU this hard...racing in MP you will not be able to have much more cars visible than in SP.

    To make things worse - the CPU hit is still very strong although the other cars are way out of sight.

    Edit: Got ninja'd hard but I made my point.
  14. Lord Kunos

    Lord Kunos His master's voice. Staff Member KS Dev Team

    you are right, it's entirely possible that the number of visible cars can have an impact on low spec systems because UE4 is using more threads than AC for rendering, thus they could go and interfere with physics threads.
  15. Coanda

    Coanda Alien

    Could you please explain the 4 cores disabled comment?

    I was considering a 8700k with a vive pro. Please dont tell me that's the quality of graphics you are viewing through VR. If so I will invest in a 32:9 monitor instead.
  16. Arpadian

    Arpadian Racer

    all settings on HIGH, Temp AA high, No Volumetric Fog, foliage in low 1600x900 in race with 15 cars visible get solid 50-60fps
  17. BrunUK

    BrunUK Alien

    I meant how many AI opponents, and the number visible. For example can you run 20 opponents with 10 visible?
  18. BrunUK

    BrunUK Alien

    I disabled cores just to make sure the CPU was the bottleneck. That's why graphics settings were also reduced to minimum resolution and quality.
    Coanda likes this.
  19. Arpadian

    Arpadian Racer

    20 AI make the game run in slideshow thats my cpu bottlenecking the physics

    but as i said before, i don't care about sp and racing vs AI, i care only for MP and so far works fantastic the only annoyance is the cpu warning message that doesn't matter for me since i have a solid smoothness racing online

    as someone said before a option to TURN OFF the cpu warning would be very welcome
  20. Lord Kunos

    Lord Kunos His master's voice. Staff Member KS Dev Team

    any chance you could try without this magic tool?
Similar Threads
Forum Title Date
ACC Multiplayer High CPU Usage with BIG (40+) MP Grids Saturday at 12:45 AM
ACC Troubleshooting CPU usage warning at Paul Ricard pits Sep 29, 2019
ACC Multiplayer Dedicated Server - Excessive CPU Usage (stable 1.0.7) Aug 9, 2019
Troubleshooting - Workarounds Abnormally high CPU usage Jul 15, 2019
ACC General Discussions Optimisation for less CPU usage! Jun 4, 2019
ACC Troubleshooting Huge FPS drops and CPU usage warning Apr 4, 2019
ACC Multiplayer CPU usage server insane in 0.6 version (loop?) Mar 4, 2019
ACC Troubleshooting Very high CPU usage in Multiplayer Jan 21, 2019
Troubleshooting - Workarounds Low FPS / High Main_T with low CPU Usage Jan 14, 2019
Troubleshooting - Workarounds weirdly low cpu and gpu usage Jan 7, 2019
ACC Graphics - Tracks and Cars Low GPU and CPU usage on lower settings Oct 29, 2018
Troubleshooting - Workarounds Low CPU and GPU usage May 7, 2018
Troubleshooting - Workarounds Fps low, cpu gpu usage low Jan 4, 2018
Troubleshooting - Workarounds Online CPU OCCUPANCY>99%, while CPU usage is around 30% Dec 23, 2017
Troubleshooting - Workarounds Low performance with low usage CPU and GPU Nov 29, 2017

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice