It doesn't seem to be even directly related to the Zen 5 launch, as the problem affects Zen 4 equally, and it looks like Windows has been leaving performance on the table for years, while AMD were completely unaware of the fact.
This only came to light as a result of investigation by Wendell from Level1Tech, who noticed the discrepancy between AMD-provided Zen 5 performance numbers with his own, as well as the performance variability between different BIOS settings. Meanwhile, AMD has been running their internal benchmarks using Admin account, and recommended the same in the official reviewers' guide. Not sure if such ignorance makes them look better or worse in this entire mess.
At least the initial reviewers' guide did not mention Admin account at all. And BTW, just to be clear: this does not mean "Account with administrator privileges", which would be normal for testing, but the (normally hidden) "administrator" account which has UAC completely disabled and hence should never be used for any real work. Why would you even test your hardware with such an obscure setup that no actual user will be using? Note that this account is not readily available but needs to be explicitly activated in an admin command prompt with
Choosing to run specific applications with elevated privileges is enough to get the performance gains for those. Still not safe, but much safer than logging in with the Administrator account.
This only came to light as a result of investigation by Wendell from Level1Tech, who noticed the discrepancy between AMD-provided Zen 5 performance numbers with his own, as well as the performance variability between different BIOS settings. Meanwhile, AMD has been running their internal benchmarks using Admin account, and recommended the same in the official reviewers' guide. Not sure if such ignorance makes them look better or worse in this entire mess.