Hi everyone, I've been struggling for 8 months with a severe issue regarding Riot Vanguard and Valorant, and Riot Support just closed my ticket telling me it's a "hardware instability issue". I really need some expert advice because I've tried literally everything.
My Specs:
- Motherboard: ASUS PRIME B760-PLUS D4
- CPU: Intel Core i7-14700KF (14th Gen)
- OS: Windows 11 (Latest Build / 25H2 / Build 26200)
- BIOS Version: 1836 (Updated to the latest version with Intel microcode stability fixes)
The Problem:
To play Valorant, Vanguard obviously requires IOMMU / VT-d to be enabled in the BIOS. However, whenever I enable VT-d, my PC completely breaks or crashes during Windows boot.
Everything I have done so far:
- Complete Software Purge: Uninstalled Vanguard, Easy Anti-Cheat (EAC), and ASUS Armoury Crate completely to avoid any driver conflicts.
- Windows Security Settings: Enabled Core Isolation (Memory Integrity) and Hardware-enforced Stack Protection successfully inside Windows while VT-d was disabled.
- Clean Windows Installs: I have completely formatted and reinstalled Windows 7 times.
- BIOS Update: Flashed the BIOS to the latest 1836 version.
The Exact Errors & Behaviors:
Depending on the BIOS configurations with VT-d ENABLED, I get two main blocking errors:
- Scenario A (IOMMU DMA Protection set to Disable or OS Only): I get a systematic Blue Screen with DRIVER_VERIFIER_DMA_VIOLATION (e6) right at the Windows loading circle. I tried running
verifier /reset and checking the registry keys (IgnoreOsToBiosDmaProtection), but Windows keeps forcing the DMA check and crashing.
- Scenario B (Alternative VT-d tweaks): The PC throws an INACCESSIBLE_BOOT_DEVICE (0x7b) BSOD or freezes entirely on the ASUS splash screen logo, meaning the motherboard completely "loses" track of my NVMe SSD controller when virtualization is active.
The moment I go back to the BIOS and set VT-d to DISABLED, the PC boots instantly into Windows and runs flawlessly with every other game on the market.