An Early Look At The AMD P-State CPPC Driver Performance vs. ACPI CPUFreq

Written by Michael Larabel in Software on 22 September 2021 at 09:38 AM EDT. Page 2 of 6. 28 Comments.
Ryzen 9 5950X AMD P-State

First up was the AMD Ryzen 9 5950X running at stock speeds (differing reported frequencies in the system table due to what each driver configuration was exposing via CPUFreq) with the Radeon RX 6800 XT for some Linux gaming.

Ryzen 9 5950X AMD P-State

First up was a look at Dota 2 that is rather CPU bound with today's high-end hardware... As expected, the best performance with either driver was when using the "performance" governor. But when using schedutil or ondemand, the amd-pstate driver saw much lower performance on this particular system...

Ryzen 9 5950X AMD P-State
Ryzen 9 5950X AMD P-State

The Ryzen 9 5950X CPU power consumption though was 10~13 Watts lower with amd-pstate paired with the schedutil/ondemand governors. But for the size of the performance hit, the perf-per-Watt for ondemand was comparable while with schedutil was worse than acpi-cpufreq.

Ryzen 9 5950X AMD P-State
Ryzen 9 5950X AMD P-State
Ryzen 9 5950X AMD P-State

With Batman: Arkham Knight running on this system through Steam Play, it was another case of amd-pstate with ondemand and schedutil governors showing noticeably lower performance and not yielding better perf-per-Watt at least for this Ryzen 9 5950X desktop on schedutil while ondemand happened to see better efficiency but at a huge performance cost.


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