Microsoft Tests Intel APX Support in Windows 11

Microsoft is testing a new setting called Advanced Performance Extensions (APX) in Windows 11 Insider Preview builds. The experimental toggle allows the operating system to utilize Intel's APX technology, which expands the x86-64 instruction set by doubling the number of general-purpose registers available to 64-bit applications from 16 to 32 and introducing three-operand instruction formats.

Intel estimates that software optimized for APX could require 10% fewer memory reads, over 20% fewer memory writes, and roughly 10% fewer instructions compared to the Intel 64 baseline. To achieve these gains, developers must recompile applications using specific APX flags.

Compatible hardware is not yet available. The technology is designed for Intel's next-generation desktop CPUs, codenamed Nova Lake (Core Ultra Series 4), and Xeon 7 Diamond Rapids data center processors, both expected in early 2027. Nova Lake chips will require new motherboards. AMD is collaborating with Intel to bring APX support to its own future processors, potentially starting with the Zen 6 family.

Microsoft has not confirmed if the feature will move from the experimental Rubidium development branch to a stable public release.