It’s probably fair to say that Windows 11 and AMD Ryzen processors haven’t seen their best times lately. Problems with CPPC2 were discovered as soon as the original version of 21H2 was released last year. This was later fixed with a chipset driver update.

Now, with the latest release of Windows 11 version 22H2, a new issue appears to be related to bugs in Zen 4-based Ryzen 7000 series processors. CapFrameX (CFX) discovered this when it was a 16-core CCD (CPU Compute Pattern). With Ryzen 9 7950X enabled, the configuration may outperform the default dual CCD 7950X. Each Zen 4 CCD has eight cores along with the cache, so essentially an octa-core Zen 4 CPU may outperform a 16-core variant with more cores.

To better understand the issue and evaluate the scenarios affecting the issue, CFX decided to test two more cases with simultaneous multi-threading (SMT) disabled. Thus, in the case of a single CCD with SMT disabled, the 16-core, 32-thread 7950X is now downgraded to an eight-core, eight-thread CPU.

Similar to the single CCD state, the SMT off state also gave similar results, performing better with fewer threads. This doesn’t seem like an isolated case either, as veteran hardware tester Hardware Unboxed (HBU) noticed a similar issue on the RTX 4090 test system, and it seems to be happening a lot more lately.

The performance issue seems to be common in Windows 11 22H2 and Windows 11 22H2 seems to be a timer issue on new Ryzen 7000 CPUs so extra threads don’t help. It could also be a driver error similar to the Nvidia fiasco that occurred recently. Maybe the GPU driver itself isn’t handling the extra threads correctly. Source