Intel terminates x86S initiative — unilateral quest to de-bloat x86 instruction set comes to an end

In the first sign of changes to come after the formation of a new industry group, Intel has confirmed to Tom's Hardware that it is no longer working on the x86S specification. The decision comes after Intel announced the formation of the x86 Ecosystem Advisory Group, which brings together Intel, AMD, Google, and numerous other industry stalwarts to define the future of the x86 instruction set.

Intel originally announced its intentions to de-bloat the x86 instruction set by developing a simplified 64-bit mode-only x86S version, publishing a draft specification in May 2023, and then updating it to a 1.2 revision in June of this year. Now, the company says it has officially ended that initiative.

"We remain deeply committed to the x86 architecture, as demonstrated by the creation of the x86 Ecosystem Advisory Group in collaboration with AMD and other industry leaders. This initiative reinforces our dedication to securing a strong future for x86, building on decades of software compatibility. While we have pivoted away from the x86S initiative, our focus remains on driving innovation and collaboration within the x86 ecosystem." - Intel spokesperson to Tom's Hardware.

Intel's decision to cease work on x86S makes sense. Any significant changes to the specification will require cooperation with AMD to ensure full interoperability and backward compatibility. Such is the nature of the 46-year-old x86—Intel and AMD are the only two primary x86 architecture licensees that build new processors in high volumes, creating a duopoly that requires standardization. 

It's also best if large software vendors and other ecosystem players add their full support, which is the crux of why the companies created the x86 Ecosystem Advisory Group. It's certainly best to have a unified, holistic ecosystem as x86 faces new challenges from Arm in both the consumer and data center markets. 

When Intel and AMD announced the group in an extremely rare joint announcement earlier this year, it was unclear how existing initiatives would be impacted. However, it certainly wouldn't make sense for Intel to forge ahead alone on x86S now that it can better ensure interoperability with any changes to the standard. Intel is also undertaking the largest layoff in the history of the company and a restructuring, which might have also played a role. That's not to mention the company is on the search for a new CEO.  

For now, it's unclear if any of the modifications that Intel made with its x86S initiative will come to fruition through the new x86 group. If they do, it will not be a unilateral decision on Intel's part — there will surely be plenty of discussion among the interested parties before any far-ranging changes are made. Naturally, that can be an issue with standards bodies and other groups, as getting a large group of stakeholders to agree on the finer points can slow progress and limit agility (we've seen that play out a thousand times).

Intel also has other future-looking x86 initiatives underway, such as its Flexible Return and Event Delivery (FRED) and the new AVX10 spec. Intel has confirmed that those initiatives are still underway.

Edit 12/20/2024 4:20am PT: Added Intel response that FRED and AVX10 initiatives are still underway.