Consistent 1 Hz stutter in Windows 11 with HAGS enabled (Ryzen 5600 + NVIDIA) — Temporarily resolved by Alt+Tab/Game Bar, flawless on Windows 10

Problem Description

In all 3D games with Hardware-Accelerated GPU Scheduling (HAGS) enabled, periodic micro-stutters occur in Windows 11 at a fixed cadence: exactly once per second (~1 Hz).

How it manifests: The stutters don't necessarily start right after launching the game. They usually appear after some playtime—most notably after changing in-game areas, switching through menus, or during scene loading/asset streaming.

• Key Symptom (Temporary Fix): Simply performing any window focus action—such as pressing Alt+Tab (minimizing and restoring the game) or opening and closing the Xbox Game Bar (Win + G)—instantly and completely resolves the stuttering. The game runs perfectly smooth again. However, after some time (or after another area/scene loads), the 1-second stutters inevitably return.
• Contrast with Windows 10: On Windows 10, running on the exact same machine, in the exact same games, and with HAGS enabled, everything works flawlessly with zero micro-stutters. This issue is strictly tied to Windows 11 and has persisted since the OS was released.

• CPU: AMD Ryzen 5 5600 (6 Cores / 12 Threads)
• GPU: NVIDIA GeForce RTX 4070
• RAM: 32 GB (Dual Channel)
• Motherboard: ASUS B550 (BIOS updated)
• Operating System: Windows 11 (the issue has occurred across all versions, from the very launch of Windows 11 up to the latest builds).
• Reference Baseline: Windows 10 (runs completely smooth on the exact same hardware).

Troubleshooting Already Attempted (Did NOT solve the issue)

1. Clean OS Installations:
   • The issue occurs immediately on a clean install of Windows 11, without any third-party background software (RGB controllers, overlays, third-party antiviruses). A fresh OS install, the graphics driver, and a single game (e.g.,) reproduce the problem right away. Tested repeatedly over the years across various Windows 11 builds (from early launch builds to the latest updates). MPO (Multi-Plane Overlay):

     Disabling MPO via the registry (OverlayTestMode = 5, DisableOverlays = 1) does not fix it.
     
     **Display and Presentation Settings:**
     
        Toggling "Optimizations for windowed games" on/off.
     
           Checking "Disable fullscreen optimizations" in the game executable's compatibility settings.
     
              Modifying GameDVR and FSE registry parameters.
     
                 Switching between Exclusive Fullscreen and Borderless Windowed modes.
     
                 **Drivers and Peripherals:**
     
                    Clean driver installations using DDU in Safe Mode.
     
                       Testing numerous NVIDIA driver branches over time.
     
                          Completely disabling the NVIDIA High Definition Audio device/controller.
     
                             Disconnecting all unnecessary USB devices (testing with only a mouse connected).
     

2. BIOS & Power Management:

Disabling AMD fTPM in BIOS.

• Toggling Resizable BAR on and off.
• Disabling HPET (High Precision Event Timer) in both BIOS and Device Manager.

Disabling Core Isolation / Memory Integrity (VBS) and hardware virtualization.