9950X3D2 Core Affinity

[Adenoid]

Any X3D2 owners out there have weird thread scheduling/affinity behavior? New build, 9950X3D2, new Windows 11 Pro install, latest BIOS on an X870E-E board w/ latest chipset drivers. Random games will be set by Windows to CCD2--if I look at the affinity they are set to core 16-31 only, 0-15 are disabled. This isn't the usual thread scheduling you'd expect to see (all core affinities enabled, but just 0-15 being used for games). The games that are affected are completely random as well. So far I have seen it with Nioh 3, Grim Dawn, Alaloth, and King Arthur Legion IX.

At least with Nioh 3 the performance is crippled to being unplayable--about a 30-40% performance hit with wild fluctuations--unless I open task manager and change it to all cores (works normally if I do that) or use Process Lasso.

[Jeremy Collake]

That's the kind of behavior we see when Windows' game detection and the AMD 3D V-Cache Performance Optimizer driver disagree about which CCD to prefer. On a dual-CCD X3D part, games are supposed to be steered onto the V-Cache CCD, but the Xbox Game Bar detection that drives that logic is unreliable, and when it misfires you get exactly what you're seeing: a title parked on the second (frequency) CCD with the cache cores idle, and a big FPS hit.

As you've noted, Process Lasso can pin this down for you so it's not random:

• For each affected game, right-click its process, choose CPU Affinity, then Always, and select the V-Cache CCD cores (whichever of 0-15 / 16-31 carries the 3D V-Cache on your chip; CPU-Z or Ryzen Master will confirm which). That rule is persistent and reapplies every launch, so you won't have to touch Task Manager again.
  
• If you'd rather not hard-restrict cores, use CPU Sets instead of Affinity for the same processes. It's a softer hint the scheduler can still lean on, and it tends to play nicer with games than a hard affinity mask.
• Worth checking that the AMD chipset driver (with the 3D V-Cache Optimizer) is current, that Xbox Game Bar is enabled, and that your UEFI (BIOS) preferred CCD setting is correct since that's the stock path that's supposed to handle this. The Process Lasso rule above will override it deterministically regardless.