Stutters and how to prevent them
Are you experiencing stuttering and frame drops in iRacing? This article offers practical solutions to help you optimize your setup and minimize stuttering, ensuring smoother and more enjoyable races.
Below you will find tips to:
- Help optimize your iRacing settings to reduce resource usage
- Configure Windows settings to maximize performance
- Troubleshoot possible hardware issues that may cause stutters
Before you start you should make sure that your graphics drivers are up to date and all available Windows Updates are installed. You can follow this guide to perform a clean installation of the graphics drivers: https://support.iracing.com/en/support/solutions/articles/31000165397-performing-a-clean-install-of-graphics-drivers
If you haven’t done so, we recommend quickly running through our quick troubleshooting guide found here: https://support.iracing.com/en/support/solutions/articles/31000169262-quick-troubleshooting-guide-sim-won-t-load
TABLE OF CONTENTS
iRacing Settings
Now that we know everything is up to date let’s look at some iRacing settings that can be changed to combat this problem.
Limiting Frame Rate
While running with uncapped framerates may seem like a good idea, it can sometimes cause large swings in performance and a less smooth image. Because of this, running a steady number of frames can often make iRacing feel smoother without over-taxing your hardware. This can help keep temperatures cooler and performance more consistent.
Although the recommended FPS limit will vary greatly between systems and users expectations, a good rule of thumb is to use a frame limit of 120 FPS for a 60Hz monitor. Higher refresh rate monitors should be limited to the refresh rate of the monitor. Some users also find that limiting the framerate to 2-5 FPS below the frame rate of the monitor provides best performance, such as a 160fps limit on a 165Hz monitor.
FPS is not linear, the difference between say 30 FPS and 60 FPS is significant but the difference between 80 and 110 FPS is much less noticeable.
The information below will help you quickly identify the refresh rate you are currently using.
To find the monitor's refresh rate in Windows access the Advanced Display options in the System > Display menu:
Here you will find the monitors selected refresh rate. Generally, you want this to be the highest available option. In this case we can see that it is set to 165Hz.
Now set the frame rate limit in iRacing to the the desired value:
If your system struggles to maintain 60 FPS, consider lowering your graphics settings. You may also want to let let iRacing pick the recommended graphics settings for your system. To do this, try shutting down the SIM and accessing the Settings menu in the UI. Then select the Interface tab and use the Graphics Config button to re-run the graphics configuration.
Note: Some 4K and Ultrawide displays such as the Samsung Odyssey G9 and G9 NEO are known to cause stability and stuttering issues in the 240Hz display mode. If you are using a 4k 240Hz display, try lowering the refresh rate to 120Hz.
Graphics Settings
Limiting the number of prerendered frames can help reduce perceived input latency, but can also introduce issues, especially stutters.
1. Open the iRacing graphics options
2. Set the Max Prerendered Frames value to 1 and test, then try increasing the value. If you have a multi-GPU setup you may need to set this value higher to match the number of graphics cards in use.
There are several options in the middle row of the options menu that can heavily impact performance with little visual gain.
"Number of Lights" control how many lights draw shadows, try limiting this to 3 or lower.
Using a high level of shadow filtering can cause stutters, try using the pcf4 filter or no filter at all.
Dynamic and fixed cubemaps can cause performance issues, set these to 0.
Some NVIDIA users have reported issues when using Reflex and GSYNC, if these settings are enabled, try temporarily disabling them and see if your issues improve.
Lower the Number of Cars Received and Rendered
The amount of processing required to render a scene is highly dependent on the number of cars. Lowering this can be an easy fix to graphical issues.
1. Open the iRacing graphics options.
2. Lower the number of Max Cars in the text box, and use the dropdowns to lower the number of cars rendered. Lowering the number of pits may help as well.
Replay Spooling
Users that have their Documents/iRacing directory in the same directory as their iRacing installation can often see stutters in longer sessions as the large replay files created during long sessions with spooling enabled can eventually lead to page faults. This is also common when iRacing is installed on a spinning HDD disk drive instead of an SSD. Unchecking "Enable replay spooling" in the Replay menu may prevent stuttering for these users.
Display Modes, VSYNC, G-SYNC/FreeSync, Nvidia Surround/AMD Eyefinity
Some users report that running the SIM in Fullscreen or Windowed prevent, some report stutters only begin after minimizing or alt-tabbing out of iRacing.
Other users report that disabling enabling various refresh rate settings like VSYNC, G-SYNC, or FreeSync resolved their stutters. Try different settings to see if performance improves.
Users have also reported similar issues with Nvidia Surround and AMD Eyefinity, especially when used with G-SYNC or similar features, which is not officialy supported by NVidia. iRacing recommends not using these features and instead using iRacing's multi-monitor support. See our guide for Setting Up Three Monitors
If you find that a certain display setting provides more consistent performance but prefer to use different settings, please contact support for additional troubleshooting.
VR: Disable Asynchronous Reprojection (SteamVR) or Asynchronous SpaceWarp (Oculus)
This can sometimes have different names, but the functionality remains the same: a single frame is repurposed and used a second time after some slight motion is applied. This can feel like a stutter because it is functionally similar to one.
1. For SteamVR, click on the display mirror and then hit Shift + A to disable Asynchronous Reprojection until SteamVR is restarted
For Oculus, click on the display mirror and then hit Ctrl + NumPad_1 to disable Asynchronous SpaceWarp until Oculus is restarted.
Simagic Alpha Wheelbase and Haptic Pedal Reactor
We are currently investigating performance issues related to the Simagic Alpha Series wheelbases and Simagic Haptic Pedal Reactor.
Users have reported performance issues when using the Alpha series wheelbases in 360Hz mode and when using the Haptic Pedal Reactor, these issues seem to be related with the high polling rate of these features causing USB bus flooding (see USB Issues for more info).
360Hz for Alpha series wheelbases can be disabled by setting the line "loadSimagicAPI=0" in Documents/iRacing/app.ini.
Haptic Pedal Reactor functionality can be disabled by unchecking "vibrate pedals" in the Option Menu after launching iRacing.
Windows Settings
Microsoft’s Windows power settings can sometimes default to less-than-ideal options for SIM Racing. Because of this you should check that the correct configuration is selected to maximize performance. Below are a couple of items you should check that have been known to cause issues for users.
Power Plan
Edit the power plan in Windows Control Panel\Hardware and Sound\Power Options
The default “Balanced” setting can cause issues for some users. We recommend using the “High Performance” option shown here.
Core Parking
Core parking is a feature that allows the computer to shut down CPU cores to save power that can cause stuttering for some users. It should be turned off when using the "High Performance" power plan, but some users report having to manually disable core parking using the following steps:
https://gigperformer.com/docs/ultimate-guide-to-optimize-windows-for-stage/coreparking.html
Power Throttling
Start all applications you would normally use for iRacing, including the SIM. Using Windows Task Manager access the Details page and select to show the Power Throttling column. Make sure the option to power throttle any applications you use for iRacing is set to disabled.
If Windows is placing iRacing into Efficiency mode, try the following :
- Go to 'Settings' > 'System' > 'Display' > 'Graphics'.
- Browse for the iRacingSim64DX11 executable or add it if it's not listed.
- Once added, click on the application and choose 'Options'.
- Set the graphics preference to 'High performance'.
- Restart the computer
Third-Party Applications and Background Applications
Third-party applications, especially ones that draw overlays, can cause stutter issues for certain users. Many applications bundled with hardware marketed as "Gaming tools" or "RGB controllers" such as ASUS ArmoryCrate/AURA, GIGABYTE Control Center, Alienware Command Center, and others are also known to cause stutter issues, as they require low-level access to volatile parts the system to function.
We recommend disabling all third party applications and background applications as a test, and then introducing the processes back as part of the troubleshooting process.
USB Issues
Much of the hardware we use for iRacing is connected via USB. When a USB device connects to the PC it is common it will cause a visible stutter in performance as it resets the USB port. Using low-quality, self powered USB hubs have been notorious for causing many issues for users. If you are having performance issues it is best to remove any unnecessary USB devices and make sure that all devices are plugged directly into the PC.
AMD systems using B550 and B650 motherboards are especially prone to USB issues, as there is a limited bandwidth on the shared PCI/USB bus on these boards compared to other models. Users with B550/B650 boards, high power GPUs, and NVMe drives are the most prone to seeing issues related to USB.
Any changes to the USB or PCI load can improve these issues, such as removing USB hubs and unnecessary USB devices, switching devices to different USB ports, moving iRacing to a non NVMe drive, or changing the PCI mode in your BIOS.
If you are experiencing USB disconnects when driving over specific parts of the track, it is possible there is a fault in the USB cable or internally in the wheel rim or base.
Sound Driver updates
An increasing number of users who are experiencing stuttering issues were resolved by updating outdated sound drivers. The majority of users are using the sound card built into their motherboard.
Often times Windows will install a universal driver for these devices that works well almost all of the time but it might be worth visiting the manufacturer's website for your motherboard and downloading the latest sound drivers.
BIOS Updates
The BIOS is the bridge between the hardware and software of the computer. We have seen a number of users have resolved issues with BIOS updates. This can be due to many different reasons such as issues with BIOS versions not working well with updated graphics cards, CPUs, sound devices, or USB devices.
It is good practice to keep your BIOS up to date and highly recommended if yours has not been updated in quite some time.
Intel motherboards supporting 13th/14th gen CPUs have received multiple BIOS updates with microcode changes to address stability issues that can cause crashing, stutters, and even physical damage to the CPU. AMD boards, especially B550/B650, have historically had issues with USB drivers that can be resolved in later BIOS updates, as well as for compatibility with newer Ryzen CPUs. We highly recommend updating to the latest BIOS on these systems especially.
Go to https://flashmyboard.com/, follow the instructions, and enter your motherboard model to find the latest BIOS for your computer.
Additional Windows Troubleshooting
Windows Updates will often automatically try to run in the background of the SIM, always ensure all Windows Updates are installed before launching iRacing.
As iRacing runs, additional files in the form of replays, telemetry, paint textures, etc need to be generated. Ensure there is at least 30GB of free space on the drive Documents/iRacing is located in, as well as the drive iRacing is installed on, if it is a different drive.
Errors or events in other processes can cause system interrupts that appear as stutters while iRacing. Any events that appear in the Windows Reliability Monitor while iRacing is running could be related to stuttering issues.
Occasionally, Windows system files can become missing or corrupted. This can cause performance issues. Windows has a built in system health check and repair tool that may resolve these issues. To run the Deployment Image Servicing and Management (DISM) and System File Checker, perform the steps:=
1. Open the Start Menu
2. Search for Command Prompt, right-click the top result, and select the Run as administrator option.
3. Copy and paste (using Ctrl+V or the right mouse button) the following command to repair the Windows image and press enter:
DISM /Online /Cleanup-Image /RestoreHealthQuick note: If the command appears stuck, this is normal behavior. After a few minutes, the process will complete successfully.
4. Copy and paste the following command and press enter:
sfc /scannowLatencyMon is a free tool can be used to diagnose specific drivers with long execution times that can cause system stutters. Download and run the tool from the following link and perform the steps:
https://www.resplendence.com/download/LatencyMon.exe
1. Click the Green play button to start logging
2. Click Drivers
3. Click "Highest execution (ms)" in the top column to sort by highest value
Then launch iRacing and drive around until stutters appear, switch back to the LatencyMon window, and see if any drivers have very long execution times.
Additional Support
If you are still having issues with stuttering, please contact support@iRacing.com for additional support.
Please reproduce the issue and send us a brief video. Please record the video using your GPU manufacturer's software.
Before reproducing the issue, enable all of the meters in the guide at the link below and set the meters to graphical.
https://support.iracing.com/
Please also save and send us the replay.
If the files are over 20 MB, please upload them to a shared drive/ cloud storage (Google Drive, Dropbox, etc.) and send us a link to access it.