AMD is preparing to introduce a new category of CPU core, designated as "Low Power" (LP), as part of its future Zen 6 microarchitecture. This development, revealed through a submission to the Linux kernel, suggests a continued focus on improving power efficiency, particularly for laptop battery life. These new cores will complement AMD's existing "compact" core designs, which first appeared with the Zen 4 architecture.
The compact core design, exemplified by Zen 4c and Zen 5c, is characterized by a smaller die footprint compared to standard performance cores. This allows for more cores to be integrated into a chiplet while reducing overall chip size and power consumption. While functionally similar to their performance counterparts, these compact cores often feature reduced L3 cache and lower boost clocks.
The upcoming Zen 6 Low Power cores are intended for minimal power consumption during background or idle workloads. According to AMD's Vishal Badole, these cores are identified by a specific value in the CPUID instruction, signaling a design optimized for extreme power saving. This approach mirrors Intel's Low Power Efficiency (LPE) cores found in its recent chips, which are tuned for very low power limits.
Unlike Intel's heterogeneous approach where Performance (P) cores and Efficiency (E) cores have distinct architectures, AMD's Zen cores share the same instruction set and architecture. This uniformity simplifies thread scheduling for both the chip and the operating system, ensuring that less demanding tasks are efficiently handled by specialized cores.
While Zen 5c cores are already present in some mobile processors like the Ryzen AI 7 350, and Zen 4c cores are utilized in devices such as Valve's Steam Deck, the Zen 6LP cores are expected to debut with the Zen 6 launch, likely targeting AMD's Ryzen mobile APU product lines. The integration of these low-power cores is anticipated to enable processors to operate with significantly reduced power draw, potentially extending battery longevity in future AMD-powered laptops.
One potential consideration for future designs is the impact of swapping standard compact cores for low-power variants within a core complex. If Zen 6 mobile processors maintain an eight-unit core complex and low-power cores have reduced boost clocks, this could theoretically lead to a performance regression. However, reports suggest AMD may increase the core complex size to 12 units with Zen 6, which could mitigate such concerns and offer a balanced performance and efficiency profile for mobile computing.