Microsoft Tests Intel APX Support to Boost Windows 11 CPU Performance

Microsoft is testing Intel Advanced Performance Extensions (APX) support in Windows 11, potentially improving CPU performance and efficiency for compatible processors.

Windows enthusiast Xeno discovered an APX toggle in Windows 11 Insider Experimental Build 29695, which uses Microsoft’s upcoming Rubidium platform.

The option allows developers to enable APX support, although users must restart their systems for the change to take effect.

Intel APX Could Improve Windows 11 CPU Performance

Intel introduced Advanced Performance Extensions in July 2023 to improve the performance and efficiency of 64-bit applications.

One of its main improvements doubles the number of general-purpose CPU registers from 16 to 32, allowing processors to handle more data without repeatedly accessing memory.

According to Intel’s simulations, software compiled to take advantage of APX could achieve 10% fewer memory load operations, more than 20% fewer memory store operations, and approximately 10% fewer instructions overall.

However, these figures come from simulations rather than real-world benchmarks, so actual performance gains will depend on the processor, software, and workload.

APX also introduces several instruction-set improvements designed to reduce unnecessary operations. New Data Destination (NDD) allows instructions to use three operands, reducing register movements, while conditional instructions can limit branching and its associated performance penalties.

The No Flags (NF) feature avoids unnecessary updates to processor status flags, while PUSH2 and POP2 improve efficiency when saving and restoring registers. APX also adds support for 64-bit absolute direct jumps.

When Will Intel APX Support Reach Windows 11?

Microsoft is currently testing APX support in the Rubidium development branch, which could eventually provide the foundation for Windows 11 version 27H2.

However, enabling the feature in Windows alone will not automatically improve performance across all applications. Users will need compatible Intel processors and software specifically compiled to take advantage of the new instructions.

Microsoft has not announced a release date for APX support in a stable Windows 11 version, and the feature’s appearance in an experimental build does not guarantee its inclusion in the next major update.

In other news, Microsoft is testing Project Pantheon, a new take on Windows Recall, while the company has also introduced Reactor to simplify Windows 11 app development without XAML.

Via Neowin