Windows 11 Adds Support for Intel's APX Instructions Ahead of Compatible Hardware
Microsoft has introduced an Advanced Performance Extensions toggle in Windows 11 for Insiders, preparing the operating system for future processors that will support Intel's instruction set expansion announced in 2023.
Intel's Advanced Performance Extensions, commonly referred to as APX, promises to deliver performance gains for certain applications once compatible processors arrive on the market. Currently, no shipping chips support the technology.
A fresh "Advanced Performance Extensions (APX)" setting surfaced in Windows 11 on October 23 when Microsoft released a new build to Windows Insiders, designed to activate performance improvements on chips that can handle it. For now, such processors remain unavailable. When they eventually ship, users running compatible hardware will be able to enable this feature. Neowin reported the discovery after an X user initially spotted it. The option appeared in build 29295 as an Experimental build, suggesting it may not reach the stable Windows 11 release for some time.
Intel unveiled APX during 2023, detailing that it introduces 16 extra general-purpose registers alongside three-operand instruction formats featuring a dedicated data destination register for numerous integer operations. Expanding the count of general-purpose registers from 16 to 32 enables code written for APX to execute with "10% fewer loads and 20% fewer stores than Intel 64's baseline," according to Intel. The GCC compiler has supported APX since version 14, with later iterations including GCC 17—which aims for a 2027 code freeze—providing expanded compatibility. LLVM and MSVC offer early-stage support as well. Despite steady progress over the last two years, developers must recompile their applications using the appropriate flags to allow APX-capable processors to take advantage of these new instructions.