iRacing Graphics Setup. – Byte Insight (2024)

Posted on November 1, 2022 by Max

What performance can be expected?

The graphics performance you will be able to obtain is based on a number of criteria including FPS (Frames/Second) or Hz (Screen Refresh Rate) and the number of pixels the GPU has to draw. Some common pixel counts are:

HP Reverb G2s – 2160 pixels squared per eye – 2160 x 2160 x 2 = 9331200 pixels
Triples on Full HD – 1920 x 1080 x 3 = 6220800 pixels = 67% of VR
Triples on 4K – 2560 x 1440 x 3 = 11059200 pixels = 119% of VR
G9 Super Wide Screen – 5160 x 1440 x 1 = 7430400 pixels = 80% of VR

Motion Sickness in VR

With VR the human response to low FPS can be worse than with screens and users often report motion sickness. Personally, I noticed it at around 70FPS, but I have one eye thats slow to focus, other racers tell me they are okay down to 50fps. The point is that in VR with no real world view when your virtual world starts to stutter your brain has no reference point to work with and then you start to feel sea sick. A fan blowing on the face as really helped me in VR but we diverge.

Analysis of CPU/GPU Bottlenecks

The best way to determine where we can improve performace is to look at the Frame Rate Meter in game. In particular we are interested in the R and G values. If R is higher than G it would indicate a CPU bottleneck and if G is higher than R then a GPU bottleneck.

LABEL	MEANING	SOLUTIONS	OPTIMUM
R	Rendering. The time (ms) it takes for the renderer to process a frame.	Adjust factors such as Shadows, Cube Maps, HDR, and object detail which mainly rely on the CPU.	Ideally 5.0 or lower for full-field and start of a race
G	GPU Frame Time. The time (ms) it takes for the graphics card to draw a frame.	Adjust factors such as HDR, Antialiasing (AA), mirrors, sharpening, heat haze, and distortionthat mainly rely on the GPU	Ideally 5.0 or lower for full-field and start of a race
T	Total Time – Renderer to GPU completion. Not same as R+G	See R & G	Combination of above
C	Physics Thread.	See R but also number of cars drawn.	There are 1000 milliseconds in a second and the Physics thread needs to run 60 times a second this is once every 16.7ms.
S	Skew is the amount of delay currently in the physics system	See R & C.	[0]
P	Page Faults	Cloud systems syncing can have an impact on this value. Ensure any cloud service like dropbox, onedrive is synced.	[0]

If you are running a device such as Reverb G2 with fixed FPS/Hz then you might not be able to obtain 5.0 or lower. For example: Reverb G2s max at 90FPS. 1000 ms / 90 frames = 11 so G cannot reasonably drop lower than 11.

Tuning your settings

The iRacing Forum has a whole section on technical aspects and in particular has one dedicated to VR. Within this section there are some superb nuggets that would help anyone optimise their graphics regardless of VR or screen. In particular the VR optimisation guide is helpful as it details whether something is CPU or GPU demanding and to what extent.

As of April 2024 my iRacing graphics configuration screen looks as shown below. This gives me anything from 90-100 Fps during the worst rain on a crowded track and 165 FPS during good weather on a crowded track. I could easily switch on Sharpening, Distortion etc during good weather with no discernible change in FPS. Due to the resolution of my triple 32″ 1440px screens and a fourth overhead monitor I am GPU bottlenecked – someone running 27s would likely have even better performance. Some newer tracks that are better optimised also give me better FPS.

iRacing Graphics Setup. – Byte Insight (1)

The following table is a quick reference sheet based on the VR guide (full credit to Robert Ehrling who did all the original experimenting) with my own notes added and some of which come from the iRacing UI. The VR guide was last updated in Oct 2022 so hopefully a lot is still relevant.

Description	Action	CPU/GPU	Notes
Resolution	System Specific		For VR you need this as low as possible. For screens/triples this will be as per your screen set up.
Res Scaling	None		This runs the simulation at a different resolution to the final output resolution and might have performance advantages if you are GPU bound. Requires Restart and Anti-Aliasing mode to be enabled.
UI Zoom	Personal		Allows you to scale your UI smaller or larger. Mine is set to 150%
Full Screen	Personal		Most systems perform better in full screen mode.
Border	Personal		Do you want a title bar and border?
Enable SPS	Enabled for VR Only		This enables GPU based Single Pass Stereo projections rather than gettting the CPU to render each eye individually.
Align	Personal		Positioning of the window in non Full Screen mode. Mine is set to None
Reflex	Enabled with Boost		NVIDIA specific feature that puts the device driver in low latency mode. Boost mode keeps the GPU frequency high in CPU bound cases.
Monitors			If you run triples you can set them up here and avoid using the Nvidia tool.
Gamma, Brightness, Contrast	Personal		Requires HDR to be active. Mine are all set to Zero.
Sky/Clouds	Low Setting	Mainly CPU	Low will improve frame rates but sky may appear jumpy as refresh rate is lower. Medium to high performance impact.
Cars	High Detail	CPU/GPU	Will have greatest impact during race starts. Drop to Medium if frame rate reduces.
Pit Objects	Medium Detail	CPU/GPU	Lowering this might improve frame rates when the Pit Lane and Boxes are visible.
Event	Low Setting	Mainly CPU	This is for objects around the track especially during race events where more are visible. Not to be confused with Objects below. Medium to high performance impact.
Grandstands	Low Setting	Mainly CPU	Due to the complexity and detail in the grandstands this will have a significant impact on frame rates. Good place to start if you are experience low FPS Medium to high performance impact.
Crowds	Low Setting	Mainly CPU	How do the crowds appear: Low = fronts only; Medium = front and back; and High = 3D characters. Medium to high performance impact.
Objects	Low Setting	Mainly CPU	These are the trackside objects. Medium to high performance impact.
Foliage	Low Setting or Off		Amount of 3D foliage. Medium to high performance impact. Requires Restart
Particles, Full Res and Soft	High Setting	CPU/GPU	LMH all. Performance impact evenly.
– Full Res	Tick		Gain frame rate in smoke dust but decrease overall
– Soft	Un Tick		Softens particle edges but lose frame rate
Max Cars	60	CPU/GPU	60 refers to the data that is gathered from iRacing. You want this maxed for any overlay application you use. LMH all. Performance impact evenly.
– Draw Cars & Pits	20 or lower		Draw refers to the number of cars/pits being drawn on the screen. The main number is for the main cameras and the number in brackets is for cars/pits in mirrors. You can run this at 20 or less. Lowering these can be an easy fix for better performance
Dynamic LOD, FPS, World and Cars	Default	Mainly CPU	Dynamically adjust the detail of objects to maintain min FPS. Low to medium performance.
Frame Rate / Vertical Sync	Personal		Set this as per your output device or lower. G2s are 90FPS, 165Hz monitor = 165Hz.
Max GPU Video Memory	Personal		This has now been removed from the UI although I believe you can still set it in the ini files.
Max System Memory	Personal		As above.
Max Prerendered Frames			I think this might be connected with SPS for VR. Its not always visible
Anisotropic Filtering	16 x	CPU/GPU	Improves texture quality on the edges of things like tracks and car roofs. Low performance impact.
MSAA Samples	2x & 4x	CPU/GPU	This is the preferred option especailly for users in VR. See Anti-Aliasing below and also this forum post. Medium, high to very high-performance impact.
Render Dynamic Track Data	Enabled	CPU/GPU	Rubbers, Marbles & Dust on track Medium to high performance impact
Shadow Maps & Cloud Shadows	Off	CPU/GPU	Casting shadows onto objects. Medium, high to very high-performance impact
Objects Self Shadowing	Off	CPU/GPU	Casting shadows onto static objects can be costly. Medium, high to very high-performance impact
Dynamic Objects			Casting shadows onto dynamic objects comes at a lower cost. Approx 50MB of memory
Night Shadow Maps	Disabled	CPU/GPU	Shadow Maps are preferred over Shadow volumes since the performance is slightly better but less sharp. High to very high-performance impact. (Restart Required)
Walls			Cast shadows from the walls at the cost of some performance.
Number of Lights			The number of lights that can cast shadows. More lights improve visual quality at the cost of performance.
PCF4 Filter			Type of filtering to be applied to shadow maps. Better filters cost more in terms of performance.
Dynamic Cube Maps			The number of dynamic (cars/co*ckpit) cubemaps rendered per frame.
Fixed Cube Maps			The number of fixed (track object) cubemaps rendered per frame.
Shader Quality			Visual quality from shaders. Higher detail comes at performance cost.
Hide Obstructions	Personal		This is things like the Halo.
Show Driver Arms	Personal		Showing co*ckpit items such as arms and wheels. Has performance cost. Requires Vertex shaders.
Two Pass Trees			Two pass rendering of trees creates better visuals at a performance cost.
High Quality Trees			High quality trees create better visuals at a performance cost.
*cockpit Mirrors Max**	Set to 2	CPU/GPU	High to very high-performance impact. Personally I like to use what the car would have IRL so no virtual mirror for me. Only run what you need.
Higher Detail In Mirrors	Disabled	CPU/GPU	Very high-performance impact. Frame rate killer
Headlights	Low Detail		The headlight options will hurt your frames especially the “Headlights – High Detail” option.
Headlights on track in mirrors	Disabled	CPU/GPU	Low to medium performance impact
Virtual Mirror FOV	Personal		Many VR users report that a FOV number around 45 to 70 works best. The higher its set the greater the impact.
Motion Blur	Off		This will add motion blur to things moving across the screen fast. It can affect performance especially on high resolution and multi screen set ups.
Anti-Aliasing	Disabled	Mainly GPU	How smoothly images are displayed. If you are using MSAA further up this should definitely be disabled. FXAA is good at low cost. SMAA offers high quality and higher cost. LMH performance impact.
SSR		GPU	The rain effect for puddles and road reflections. Expensive post processing. Low setting offers slight decrease in quality but recommended for high resolution systems such as triples and 4K. Rain Only recommended so costs are only occured during wet conditions.
Sharpening	Enabled	Mainly GPU	Enables sharpening effect, consumes video memory and might adversly affect texture quality. Low to medium performance impact.
Distortion	Disabled	Mainly CPU	Enables Distortion effect, consumes video memory and might adversly affect texture quality. Low to medium performance impact.
HDR	Disabled	CPU/GPU	Enables HDR effect, consumes video memory and might adversly affect texture quality. Medium to high performance impact. (Requires Restart)
Heat Haze	Disabled	Mainly GPU	Enables Heat Haze effects, consumes video memory and might adversly affect texture quality. Medium performance impact.
SSAO	Disabled	Mainly GPU	Enables Screen Space Ambient Occlusion which gives more depth to the scene by adding shadow. May affect FPS and degrade texture quality due to video memory limitations on older pCs/GPUs. It is overkill at dense resolutions and only makes sense to run it at lower vertical resolutions like 1080p. Very high-performance impact
Video Mem Swap High-Res Cars	Disabled		Recommended for PCs with limited video memory. The 3 nearest cars render in high details as these cars change.
2048×2048 Car Textures	Enabled		Use higher resultion car paint jobs. Can consume 150MB of textures.
Hide car numbers	Personal		Only applicable in test sessions.

Notes about Anti Aliasing.

“iRacing has two different AA models. There’s MSAA which is a pre-process step. It renders portions of the screen at higher than final resolution then downscales the image to final resolution. This can vary from 0x (off) to 8x and is the control directly under the anisotropic setting. Then there’s the newer post-process options of FXAA and SMAA which takes the output at final resolution and applies a smoothing filter. If you are already running MSAA (common), then FXAA will probably not have much effect (or rather, it will be hard to observe).”

Via Forum Post

Notes about Nvidia 3D Settings.

If you are upgrading or making changes iRacing recommends doing a default restore of the settings in case an old setting is holding back performance. Ideally you want to update your driver with a clean install. Do not install GeForce!

Right-click desktop and go into Nvidia Control Panel
Click Manage 3d Settings
Click restore to set everything to default for global settings or program settings
Select iRacing from Program Settings and make the following changes.
- Anti-Aliasing – Transparency: change to Multisample.
- Power management mode: Prefer maximum performance
- Vertical Sync: Off
- Virtual Reality pre-rendered frames: …. change to 1 (higher numbers have more latency 2 or 3).

iRacing Graphics Setup. – Byte Insight (2)

Do I need a new GPU and what about the CPU?

Hold on – its not all down to the GPU – the CPU does some heavy lifting as well! The actual numbers here are very game dependant. Some games are better at utilising multiple cores/threads than others. iRacing is renowned for running on limited cores/threads due to the age of the engine. However, a visit to the Gaming Bottleneck Calculator can show us how different combinations of CPU/GPU might perform in iRacing. Although unfortunately we have to use Assetto Corsa as our test game for these calculations below.

CPU	Resolution	Pixel Count	3070	4080
i9 10850k	2560 × 1440	3686400	-36.7% CPU	-77.3% CPU
	4096 x 3072	12582912	-34.2% GPU	-2.6% CPU

What’s noticeable in the table above is that as our resolution reduces we are placing higher demands on the CPU and its there the bottleneck occurs. I’m told this is due to increased FPS but cannot support that with evidence (readers – help me out here).

The other thing that complicates any new GPU purchase is that series and models are not linear in their performance growth. That is to say a 3080Ti might be a better purchase than a 4070Ti. You can compare all the chip specs on the Nvidia Comparison Page or all GPUs on a Comparison Website.

Prior to the introduction of rain there were people in my league discord doing very well in both lap times and race craft running 2080 cards on 27″ 1080 Triples. So I’m definitely of the opinion that its not about having the latest kit but its about having the right kit working in harmony with optimised settings.

Unfortunately, as I found out recently cheaper older and very suitable kit sometimes just isn’t available to buy or doesn’t represent good value for money in the long term when you consider warranties and investment. So choosing what to buy and/or any upgrade route is never straight forward but think of the life expectancy you have for a system.

Category: Blog Tags: reverbg2s, simracing, vr

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