SSE4.2 instructions have become mandatory for Windows 11 24H2 – the OS does not load on LGA775 and AM2/AM3 systems

In February of this year, Microsoft released a test build of Windows 11 numbered 26063 as part of the Windows Insider program, which required a processor that supports SSE4.2 instructions to install. Now it has become known that a similar requirement is imposed for installing Windows 11 24H2 (starting with build 26080). If the PC uses a processor that does not support SSE4.2, the OS simply will not boot.

“Starting with Windows 11 Build 26080, Windows 11 version 24H2 requires a processor that supports SSE4.2 instructions to boot. Attempting to load Build 26080+ on systems without support for SSE4.2 instructions will result in the device automatically rebooting after reaching the loading screen phase.”says developer Bob Pony, who was one of the first to notice that Microsoft has changed the hardware requirements for installing Windows 11 24H2.

Let us recall that SSE4 instructions are an extended set of Single Instruction, Multiple Data (SIMD) instructions, support for which Intel implemented in Penryn (Core 2) processors in 2006. Support for a more advanced version of SSE4.2 appeared in Nehalem processors in 2008. AMD processors supported SSE4.2 with the launch of chips based on the Bulldozer architecture. SSE4.2 are designed to perform character lookups and comparisons on two 16-byte operands at a time to speed up XML documents, as well as CRC32 calculations for data transfer protocols.

Any x86-based processor released after 2008 must support SSE4.2. However, processors released before the first generation of Intel Core i5 and i7 chips do not have such support. Older processors such as AMD Barcelona chips that support SSE4a will not be suitable for installing Windows 11 24H2. Obviously, Microsoft’s innovation will not affect the vast majority of users, since support for SSE4.2 instructions is implemented in all modern processors.