CPU & GPU Tuning for Sim Racing

Once you know what PC you have, the next step is making sure it runs your sims efficiently. This page focuses on CPU & GPU tuning: power plans, drivers, graphics control panels and basic monitoring so you can spot bottlenecks quickly.

Set up Windows and your GPU driver so they don’t throttle performance.
Create simple game profiles instead of random “tweaks everywhere”.
Learn how to tell if you are CPU-limited or GPU-limited.

1. Get Windows out of the way

Use a High performance or similar power plan, not Power saver.
Disable aggressive sleep / idle timers while racing.
Close background apps that constantly use CPU or disk (browsers, updaters).
Make sure the sim is set to use the high-performance GPU (laptops especially).

2. GPU drivers & control panel

Keep drivers reasonably up to date, but avoid “day one” betas unless needed.
Let the game handle most settings first; only override a few key options.
Use one game profile per sim instead of global overrides.
Prefer hardware-accelerated GPU scheduling only if it’s stable on their system.

3. Spot CPU vs GPU limits

Use the sim’s built-in FPS / timing graph where possible.
If GPU usage is high and CPU low → mostly GPU-limited.
If one CPU core is pegged at 100% while GPU is relaxed → CPU-limited.
Big grids, replays and heavy AI usually hit CPU harder than GPU.

4. Safe starting point for tuning

Start from a sensible preset (Medium / High) instead of Ultra everywhere.
Change one group of settings at a time (shadows, mirrors, effects).
Test in a busy scenario: race start, night, rain, 30+ cars if the sim allows.
Write down what worked so you can reuse it on other tracks and cars.

This page works together with your PC Specs & Baseline Settings guide and the Performance & FPS checklist. Use all three when helping someone with low FPS.

Step-by-step CPU & GPU tuning

Use these steps when you already know the user’s specs and want to squeeze stable performance out of their PC. Start with Windows, then the GPU driver, then check if they are CPU- or GPU-limited.

Windows

1. Set power plan & clean up background load

Ask them to press Windows key and type “Power plan”, then open Power & sleep settings → Additional power settings.[1]
Select High performance, Ultimate performance or the vendor’s gaming plan (AMD Ryzen High Performance, etc.).
In Power & sleep, extend screen/PC sleep timers so the PC doesn’t try to sleep during long races.
Check Task Manager (<Ctrl+Shift+Esc>) and close obvious heavy apps: browsers with many tabs, cloud sync, extra launchers, video editors, etc.

Tip: If laptop users are on battery, explain that they should race while plugged in – many laptops throttle heavily on battery power.

GPU driver

2. Tidy up NVIDIA / AMD control panel

Check their driver is reasonably current, not years old. Avoid very fresh beta drivers unless needed for a new sim.[2]
In NVIDIA Control Panel / AMD Software, create a per-game profile for each sim (iRacing, LMU, ACC, etc.).
Use “Let the application decide” for Anti-Aliasing and V-Sync as a starting point.
Set Power management mode (NVIDIA) or similar to “Prefer maximum performance” for the sim profile.
Turn off unnecessary image “enhancers” (sharpen+FX, experimental latency features) unless you specifically want them.

Tip: Keep a screenshot of a known-good profile so you can send users a reference layout for their GPU control panel.

Monitoring

3. Is it CPU-limited or GPU-limited?

Ask them to enable the sim’s built-in performance graph if available (CPU / GPU bars, latency graph, etc.).
Alternatively, use Task Manager Performance tab: watch one CPU core and the GPU while they drive.
If GPU usage is ~95–100% and CPU is moderate: they’re mostly GPU-limited – lower graphics first.[3]
If one CPU core sits at or near 100% and GPU is not fully used: they’re CPU-limited – reduce AI, opponent count, mirrors, and CPU-heavy effects.
Note when FPS drops: race starts, rain, night, certain tracks. These often push CPU harder than simple hotlaps.

Tip: Tell the user in simple language: “Your graphics card is the bottleneck” or “Your CPU is the bottleneck”. It helps them understand later advice.

Advanced

4. Advanced tweaks & common mistakes

Do use a sensible FPS cap (72 / 90 / 120) to reduce spikes and stutter.
Do test one change at a time and keep a small notes file of what worked.
Don’t max out resolution scaling or supersampling on a mid-range GPU.
Don’t run heavy background recording, browser overlays and multiple dashboards at once on weaker CPUs.
Don’t chase tiny visual gains (extra grass detail) if they cost 30–40% FPS.

Tip: When you find a stable combo of sim settings, GPU profile and overlays that works well, capture screenshots and mark them as “known good” for that tier of hardware.

Sources & references

Windows documentation and common gaming guides on using High performance power plans to avoid CPU throttling during games. ↩ back
NVIDIA / AMD driver and control panel best-practice notes for per-game profiles and power management modes in 3D applications. ↩ back
Sim-racing community guides on identifying CPU- vs GPU-limited scenarios using in-game graphs and Windows performance tools. ↩ back