So it would be faster and more efficient when sticking to the new subset and Nx slower then using the emulation path.

i.e Software compiled for 86 should work on x86. The value for backward compatibility is kept with both Intel and AMD. If the market wants something in between they now have an option.

I know this isn't a sexy idea because HN or most tech people like something shiny and new. But I have always like the idea of extracting value from the "old and tried" solutions.

This isn't an issue in any way. Vendors have been routinely taking out rarely used instructions from the hardware and simulating them in the software for decades as part of the ongoing ISA revision.

Unimplemented instruction opcodes cause a CPU trap to occur where the missing instruction (s) is then emulated in the kernel's emulation layer.

In fact, this is what was frequently done for «budget» 80[34]86 systems that lacked the FPU – it was emulated. It was slow as a dog but worked.

>AMD and Intel Celebrate First Anniversary of x86 Ecosystem Advisory Group Driving the Future of x86 Computing

Oct 13, 2025

Standardizing x86 features

Key technical milestones, include:

    FRED (Flexible Return and Event Delivery): Finalized as a standard feature, FRED introduces a modernized interrupt model designed to reduce latency and improve system software reliability.

    AVX10: Established as the next-generation vector and general-purpose instruction set extension, AVX10 boosts throughput while ensuring portability across client, workstation, and server CPUs.

    ChkTag: x86 Memory Tagging: To combat longstanding memory safety vulnerabilities such as buffer overflows and use-after-free errors, the EAG introduced ChkTag, a unified memory tagging specification. ChkTag adds hardware instructions to detect violations, helping secure applications1, operating systems, hypervisors, and firmware. With compiler and tooling support, developers gain fine-grained control without compromising performance. Notably, ChkTag-enabled software remains compatible with processors lacking hardware support, simplifying deployment and complementing existing security features like shadow stack and confidential computing. The full ChkTag specification is expected later this year – and for further feature details, please visit the ChkTag Blog.

    ACE (Advanced Matrix Extensions for Matrix Multiplication): Accepted and implemented across the stack, ACE standardizes matrix multiplication capabilities, enabling seamless developer experiences across devices ranging from laptops to data center servers.

But it's fortunate that they realised the main attraction to x86 is backwards-compatibility, so attempting to do away with that will lead to even less marketshare.

Some distributions like Debian or Fedora will make newer features (such as AVX/VEX) mandatory only after the patents expire, if ever. So a new entrant could implement the original x86-64 ISA (maybe with some obvious extensions like 128-bit atomics) in that time frame and preempt the patent-based lockout due to ISA evolution. If there was a viable AMD/Intel alternative that only implements the baseline ISA, those distributions would never switch away from it.

It's just not easy to build high-performance CPUs, regardless of ISA.

So this is kind of a useless question, because in such a timespan anything can happen. 20 years ago computers had somewhere around 512MB of RAM and a single core and had a CRT on desk.

Obliterating x86 in that time would take quite a lot more than what the ARM trajectory is now. It's had 40 years to try by now and the technical advantage window (power efficieny advantage) has closed.

Mature gallery of software to be ported from TSO to weak memory model is a soft moat. So is avx/simd mature dominance vs neon/sve. x86/64 is a duopoly and a stable target vs fragmented landscape of ARM. ARM's whole spiel is performance per watt, scale out type of thing vs scale up. In that sense the market has kind of already moved. With ARM if you start pushing for sustained high throughput, high performance, 5Ghz+ envelope, all the advantages are gone in favor of x86 so far.

What might be interesting is if let's say AMD adds an ARM frontend decoder to Zen. In one of Jim Keller's interviews that was shared here, he said it wouldn't be that big of a deal to make such a CPU for it to be an ARM decoding one. That'd be interesting to see.

Lunar Lake shows that x86 is capable of getting that energy efficiency

Panther Lake that will be released in around 30 days is expected to show significant improvement over Lunar Lake

So... why switch to ARM if you will get similar perf/energy eff?

Now apply that to weapons systems in conflict against an enemy that DOES have modern production that you (no longer) have... it's a recipe for disaster/enslavement/death.

China, though largely hamstrung, is already well ahead of your hypothetical 2005 tech breakpoint.

Beyond all this, it's not even a matter of just slower, it's a matter of even practical... You couldn't viably create a lot of websites that actually exist on 2005 era technology. The performance memory overhead just weren't there yet. Not that a lot of things weren't possible... I remember Windows 2000 pretty fondly, and you could do a LOT if you had 4-8x what most people were buying in RAM.

If society as a whole reverted to 2005, we would be fine.

If you took today's software and tried running it on a memory constrained, slow, 2005 era system, you'd be in for some pain.

Why else are everything now seem to be wrappers for wrappers? What if the bloat was, subconsciously or whatever, the point?

Customer needs don't really matter in cases where monopolist (ab)uses the law to kill competition. That's the MAIN reason why monopolies are problematic.

The licensing deals that legitimized AMD's unlicensed clones came later.

Then there was the big licensing deal for Intel 8088 and its successors, which was forced by IBM upon Intel, in order to have a second source for the critical components of the IBM PC.

IP is one of those things you invent once you made it to the top.