AMD Ryzen 9 9950X Power/Performance With CPU Frequency Scaling Driver Tunables
Continuing on with the AMD Ryzen 9000 series Linux benchmarking, today's testing is looking at the performance and power impact of the AMD Ryzen 9 9950X when adjusting the CPU frequency scaling driver, governor, and Energy Performance Preference (EPP) tunable to help look at the performance and power efficiency characteristics of this current flagship Zen 5 desktop processor.
Installing Ubuntu 24.04 LTS or most other modern Linux distributions on the AMD Ryzen 9000 series will yield the AMD P-State EPP CPU frequency scaling driver being used and the "powersave" CPU frequency scaling governor and on most platforms at least will be using the "balance_performance" Energy Performance Preference. This article is looking at the impact of switching to the "performance" governor as well as trying other EPP values. Additionally, for reference are benchmarks if falling back to the older/generic ACPI CPUFreq driver in its schedutil and performance governor modes.
👁 AMD P-State Driver sysfs tunables
For this article on the Ryzen 9 9950X running Ubuntu 24.04 LTS with the Linux 6.10 kernel the following CPUFreq driver / governor / EPP configurations were tested:
- amd-pstate-epp powersave, EPP balance_performance
- amd-pstate-epp performance, EPP performance
- amd-pstate-epp powersave, EPP performance
- amd-pstate-epp powersave, EPP power
- amd-pstate-epp powersave, EPP balance_power
- acpi-cpufreq schedutil
- acpi-cpufreq performance
These benchmarks are mostly for reference purposes for providing some insight what modifications may be desired by those aiming to achieve greater performance or power efficiency on new Ryzen 9000 series desktops running Linux.
No other changes were made to the system hardware/software during testing besides the noted modifications. Note on the system table above with the difference in reported CPU clock frequency just comes down to the sysfs interface values being exposed differently between the AMD P-State and ACPI CPUFreq drivers -- the Ryzen 9 9950X was running at stock speeds for the entire benchmarking session.