Game runs on a single CPU core, Windows 11 intel i5 11600k

[KORE]

I have two identical computers for 1080p gaming, both running Intel i5-11600K CPUs and GTX 1070 GPUs. One is on Windows 10, and the other is on Windows 11. The Windows 10 system runs ONCE HUMAN at around 100-120 FPS on mid/high settings, while the Windows 11 system only achieves 30-60 FPS, regardless of the settings. The key difference is that the Windows 11 system is only utilizing a single core of its 6-core CPU, while the Windows 10 system uses all cores. I've tried numerous solutions to force the lower FPS system to use more cores, including going through NVIDIA settings, Windows settings, BIOS, and even using Steam's -USEALLAVAILABLECORES command, but nothing works.

I've checked other games as well. For example, The First Descendant also runs on one core, but the FPS difference is only around 6-10 FPS between the two systems. Interestingly, Overwatch runs on multiple cores on both systems, achieving 260-300 FPS on mid settings.

<b>Here’s a summary of the troubleshooting steps I’ve taken:</b>

Checked for Background Processes: Verified in Task Manager that no background processes were consuming significant CPU resources. I also tried a clean boot to ensure no third-party services or startup programs were causing issues.

CPU Affinity: Manually set the CPU affinity in Task Manager to ensure all cores were selected for the games. This did not resolve the issue.

BIOS Settings: Updated the BIOS and checked for any settings related to CPU power management, C-States, or core parking. I also tried resetting the BIOS to default settings.

Windows 11 Settings: Enabled Game Mode and checked if VBS (Virtualization-Based Security) was active. Disabling VBS did not improve performance. I’ve ensured all Windows updates are installed.

NVIDIA Settings: Set the power management mode in the NVIDIA Control Panel to “Prefer maximum performance” and enabled threaded optimization. I also reinstalled the latest NVIDIA drivers using a clean install.

Performance Comparison: Ran stress tests and compared CPU and GPU usage, temperatures, and clock speeds on both systems. All metrics were similar, with all cores running during these tests, except in the games I mentioned where the Windows 11 system is only using one core.

Game Reinstallation: I reinstalled the problematic games on the underperforming system, but the issue persisted.

Considered Windows 11 Rollback: As a last resort, I’m considering rolling back to Windows 10 on the underperforming PC to see if the issue is specific to Windows 11.

Despite these efforts, the problem remains. Has anyone encountered a similar issue or can suggest any other potential solutions?

[AoD_lexandro]

Sounds like a bad driver package or corrupted file in there causing issues imo. I would suggest checking for any updated motherboard drivers, specifically chipset drivers. It would also not hurt to run a sfc/ scannow command in windows to check for a corrupted OS file.