Unhealthy information for Workforce Pink: it appears that evidently AMD’s high-end Ryzen desktop CPUs – together with the flagship Ryzen 9 7950X – are having their efficiency successfully throttled by a characteristic in Home windows 11.

The characteristic in query is the Home windows 11 thread scheduler (typically known as a thread director) – primarily a easy background program that dictates which cores in a CPU ought to deal with every job given to the system. Usually, this could enhance efficiency, however it seems that the thread scheduler is having difficulties with the twin CCD configuration discovered within the Ryzen 9 7950X and 7900X.

Replace with SMT off. Disabling SMT can nearly repair the efficiency loss. What does the imply? Possibly lowering the thread pool of the sport reduces the likelihood that 2 of N threads sharing information are unfold throughout totally different CCDs as a result of N/2 over 2 is far smaller than N over 2. https://t.co/vqnG79pWKB pic.twitter.com/nP7sVpOWCuOctober 15, 2022

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To interrupt down what this implies, the brand new Ryzen 9 CPUs primarily have two CCDs (core compute dies) that comprise the cores powering the processor. Twitter person CapFrameX discovered that the Home windows 11 thread scheduler was experiencing points with the double CCD format of the 7950X, lowering efficiency in some video games by as a lot as 30%.

Disabling the second CCD introduced efficiency again up, however that primarily means you are shopping for a 16-core CPU and solely utilizing eight of them. CapFrameX additionally demonstrated that turning off Simultaneous Multithreading (SMT) boosted gaming efficiency – however once more, this implies going from 32 threads to 16, one per core as an alternative of two.

Evaluation: As soon as once more, the 7700X is the only option for avid gamers

It’s price noting that the cheaper chips in AMD’s new vary – the Ryzen 5 7600X and the superior Ryzen 7 7700X – are unaffected, since they solely have a single CCD. We have already declared in our evaluate that the 7700X is the very best of the bunch, and the neatest choose for the overwhelming majority of customers with regards to worth towards efficiency.

This subject has occurred earlier than: in 2021, the 21H2 replace for Home windows 10 noticed the up to date thread scheduler tank efficiency of Ryzen CPUs earlier than the difficulty was fastened with a chipset driver replace. AMD might want to act quick to patch this downside if it needs to keep away from avid gamers steering away from its high-end processors fully.

Frustratingly, this subject has come to mild simply days after a separate Home windows 11 patch (obtainable to Home windows Insiders) was deployed to resolve an present subject with L3 cache latency in Ryzen chips, which was additionally impacting efficiency. If we labored for AMD, we’d be sending some strongly worded emails to Microsoft proper now.