Edit: Project updated to support ALL X3D cpu.
My 9950X3D / RTX 5090 VR rig went from session-ending freezes to genuinely zero perceptible hiccups, and every fix was found by logging races and measuring, not by stacking random YouTube tweaks. I’ve put the whole method into a free, open-source guide and script kit for Both single (5800X3D / 7800X3D / 9800X3D) and dual-CCD X3D chips (9950X3D / 7950X3D / 9900X3D / 7900X3D) + NVIDIA, flatscreen or VR.
Guide: iRacing Tuning — Dual-CCD Ryzen X3D + NVIDIA
What it’s most effective at:
- The “stutters until I click the sim window” problem (VR especially). Windows 11 drops the system timer from 1 ms to 15.6 ms whenever the sim loses window focus, which the VR compositor causes constantly. This was my single biggest root cause. One registry fix ends it permanently.
- Micro-stutter from GPU interrupts. NVIDIA’s interrupts and iRacing’s main thread both default to CPU 0 and collide. The kit steers them onto your other CCD.
- Clockwork stalls every ~5–7 minutes. That cadence is Windows Update/Search scan tasks. Quieted during races, restored after.
- Constant tiny hitches from Defender scanning every texture read mid-race. Fixed with folder exclusions only - Defender stays fully active for everything else.
- Plus: USB Selective Suspend off (stops your wheel/headset USB power-cycling), Game Bar/DVR off, and pinning the sim to the V-Cache die with Process Lasso (CPU Sets, since EAC blocks hard affinity).
Edit: Project updated to support ALL X3D cpu.
Why dual-CCD specifically: the popular single-CCD guides (7800X3D etc.) recommend the Balanced power plan - on a dual-CCD chip with VR that’s actively harmful (core parking starves the compositor; I measured GPU util collapsing from 55% to 11%). This guide covers what flips and why.
The site walks you through six steps (~30 min + a reboot), adapts to your exact chip and VR/flatscreen setup, and the kit has a one-click baseline installer. Everything is readable PowerShell, everything has an undo, and there’s a logging tool so you can prove it worked instead of trusting placebo. It builds on rcsracing93’s excellent single-CCD guide, credit where due.
Smooth sailing is the goal. Even when a race ran well if the full trace found anything, I optimized. I want console optimization on my PC. We deserve it for the money we’ve spent.
Happy to answer questions or dig into anyone’s stutter logs in the comments.
Note: Single-CCD owners (5800X3D/7800X3D/9800X3D): I have updated the program to detect CPU and work for your system. Make sure you choose the right CPU (it tells you the right one) If you downloaded it from a previous version, delete it and download the latest.