AMD Ryzen's HighestFreq: Improving OS Performance Management

AMD is working on a new feature for future Ryzen processors that aims to improve how the chips interact with Windows and Linux operating systems. It introduces a new CPPC field called HighestFreq, through which the OS can directly obtain information about the real maximum frequency of processor cores from the device firmware.

The CPPC (Collaborative Processor Performance Control) technology is already employed in modern AMD processors to relay performance data and preferred core information to the system. On Linux, this data is handled by the AMD P-State driver, while on Windows it helps the system distribute tasks among cores and manage processor boosting.

Currently, operating systems have to rely on approximate performance indicators that don't always accurately reflect actual core frequencies. AMD notes that the relationship between performance and frequency is not always linear, which can lead to errors in boost calculations by the OS.

The new HighestFreq feature is designed to fix this issue. Instead of relying on rough estimates, Windows and Linux will be able to fetch the actual maximum frequency value directly from the processor. This should result in more precise load distribution across cores and better overall system performance management.

AMD emphasizes that this is not about introducing a new overclocking mode or raising processor frequencies. The change is solely aimed at improving the accuracy of task schedulers and power management algorithms.

For now, the patch is being prepared for Linux, and the feature itself is being considered for inclusion in the ACPI 6.7 standard. Future support could also come to Windows 11 if Microsoft implements compatibility with the new HighestFreq field.