**Ubuntu has added a new x86-64-v3 ‘architecture variant’ for Ubuntu 25.10, configuring its build infrastructure and package managers to support compiling and installing optimised packages. **

*“By making changes to dpkg, apt and Launchpad, we are able to build multiple versions of a package, each for a different level of the x86-64 architecture, meaning we can have packages that specifically target x86-64-v3,” *Canonical’s Michael Hudson-Doyle says.

Starting with Ubuntu 25.10, over 2000 packages are available in an “optimized form” for the “more modern x86-64-v3 architecture level”. These are available on an opt-in basis (i.e., you manually install the variant version).

But these have not been tested as thoroughly as the standard versions.

In Ubuntu 26.04 LTS, Canonical plans to create v3-enabled versions of all packages, and test them properly. It’s not bee stated if 26.04 LTS will make v3 packages default, continue to require opt-in or be available with a separate installer image.

What is x86-64-v3?

Although most modern Intel/AMD processors are 64-bit, they’re not all equal — and I don’t mean simply in terms of core count, transistor size, cache speeds, etc.

They differ in what instruction sets they support. Newer CPUs can include newer instruction sets. Packages can be optimised for those sets, which are grouped into microarchitecture levels based on the ones they support.

By default, Ubuntu uses plain amd64/x86-64 (v1), the broadest set. This is compatible with CPUs going way, way back (the CPU in my first-ever custom build PC was an AMD Athlon X2 6000+ and it can still boot Ubuntu 25.101).

Other Linux distros (further down) use v2 or v3 as their baseline. Devices with CPUs that that lack any of the required instruction sets can’t run it. CPUs with newer levels (like v4) are backwards compatible with older levels – so all v1 builds run on v4, but v4 can’t run on v1.

Packages optimised for instruction sets in x86-64-v3 (sometimes referred to as amd64v3) are available to test in Ubuntu 25.10. The most notable of these are AVX/AVX2 (Advanced Vector Extensions).

AVX/AVX2 let processors handle more pieces of data (256 bits) at a time, which (since computers compute) means potentially better/faster performance in operations that require a lot of data processing, e.g., crypto/encryption, scientific simulations, etc.

Linus Torvalds is not the biggest fan of adding instructions sets. He once publicly chided Intel for “trying to create magic instructions to then create benchmarks that they can look good on”.

There’s also a lot of uncertainty or commitment to certain parts of instruction sets, not least from Intel itself which muddies the water about what can be reliably targeted as a baseline by Linux – a contentious topic with various positions.

Is amd64v3 performance tangibly better?

For regular Ubuntu desktop users, the availability of 64-bit variant packages won’t mean a great deal.

While most CPUs made since 2015 onwards should support x86-64-v32, any tangible benefits in using optimised packages varies based on workload.

Ergo, this isn’t a *“this one change makes everything faster” *type deal for desktop users (though your favourite tech YouTubers will no doubt suggest it is). The main benefit here is AVX/AVX2 access to process up to 256 bits of data simultaneously – not everything needs it.

Back in 2013, Ubuntu released an experimental Ubuntu Server build that was optimised for v3. Testing at the time showed usernegligible to minor gains. Canonical mention performance boosts of 1% for ‘most’ v3 packages, higher for those doing intensive number crunching.

Clearly, the use of amd64v3 certainly stands to offer benefits on servers and high-performance computing (HPC) where workloads are typically data intensive, and even a modest 1% speedup can mean a measurable difference in costs.

For every day desktop users, even if benchmarks show performance in specific tasks is better, that is not the same as saying everything gets faster – or that the percentile different translates to a perceptible difference in everyday workloads.

Fashionably late

Ubuntu isn’t pushing any boundaries in making optimised architecture builds available for amd64-v3. If anything, it’s late to market — albeit intentionally so.

Red Hat Enterprise Linux 10 (RHEL) moved to a amd64-v3 baseline earlier this year, while openSUSE Leap 16 made amd64-v2 its baseline (meaning it doesn’t run on most processors pre-2008; it also provides select v3 builds in its repos, also).

RHEL’s “forced” switch wasn’t without controversy but given its customers are enterprises, where every cent in performance matters, it is of less consequence.

If Ubuntu were to make v3 its baseline, rather than, as some distros do, dynamically offer the right packages for supported systems, it would leave older devices unable run newer Ubuntu versions, similar to how most RISC-V devices can’t run Ubuntu 25.10.

However, were that to happen… A lot of care would need to be taken, and a lot of sign-posting up-front done so that users aren’t left out in the cold.

If you want to try these new packages out — caveats apply — you can do so by following the steps outlined above.

1. Not suggesting it would run a full-fat Ubuntu 25.10 install very well, simply illustrating Ubuntu’s backwards compatibility – which would be lost if it were to move to v3 as default. ↩︎
2. Some, however do not – Intel’s Jasper Lake CPUs in 2021 don’t support AVX/AVX2 ↩︎