Fix to use only the first CCD on Ryzen 9 9950X3D:
Make sure the Xbox Game Bar is installed, updated, and working. Tagging a game (“Mark as a Game”) must function correctly.
In BIOS, set CPPC to Auto. Install the latest AMD Chipset Driver so that 3D V-Cache optimization is active.
Set the Windows Power Plan to Balanced.
Then create a file named User.cfg in your game or app folder (not User.cfg.txt).
Add the following lines:
- Thread.ProcessorCount 8
- Thread.MaxProcessorCount 8
- Thread.MinFreeProcessorCount 0
- Thread.JobThreadPriority 0
Save the file, start your game or application, and check in Task Manager under Performance → CPU that only the first CCD is being used. Now it should work correctly using only the first CCD.