A recent set of Linux kernel patches has demonstrated the potential for substantial performance improvements on Valve's Steam Deck, with early testing indicating that 1% low frame rates could increase by as much as 31 percent. These improvements are largely attributed to a new feature called 'epp_boost,' integrated into the AMD P-State driver.
The 'epp_boost' feature, developed by Linux kernel hacker David Vernet, implements per-core Energy Performance Preference (EPP) for AMD CPUs. Vernet explained in a Linux kernel mailing list post that the feature was designed with gaming workloads in mind. He identified an inefficiency in existing power management strategies where frequent, short sleeps—common in gaming—could lead to performance degradation and increased tail latency. "Each sleep decays the hardware's performance signal, causing post-wakeup bursts to start at a low operating point and inflating tail latency even though the CPU is essentially fully busy while work is available," Vernet noted.
While a straightforward solution might have been to globally force EPP to its 'performance' setting, this would have negatively impacted power efficiency, a critical factor for a handheld device like the Steam Deck. Instead, Vernet's patches introduce an opt-in, per-core EPP boost.
Testing conducted by Phoronix, as reported by PC Gamer, utilized Civilization VI for benchmarks. Their results showed a 31.8% increase in 1% low FPS and a 4.1% improvement in frame times. While these gains were observed on the Steam Deck, similar AMD Ryzen systems could potentially benefit as well.
To take advantage of this performance boost, users will need to manually enable the 'epp_boost' feature by setting 'amd_pstate.epp_boost=1'. The status of the feature can then be verified by checking '/sys/module/amd_pstate/parameters/epp_boost'.