IBM unveils first dual-architecture mainframe processor, bringing Arm to IBM Z and LinuxONE
IBM Unveils Next Generation Dual-Architecture Processor
At Hot Chips 2026, IBM announced the first mainframe processor designed to natively run both IBM and Arm instructions. Built on a 2nm node with 11 cores at over 5.7 GHz, the chip lets enterprises run Arm-native Linux alongside z/OS and Linux on IBM Z, combining Arm's vast software ecosystem with IBM's security and reliability. This milestone follows IBM's April collaboration with Arm and aims to expand software choice for mission-critical workloads.
This processor represents a significant architectural advancement for IBM Z and LinuxONE. By bringing Arm natively to our platform, we're combining access to one of the industry's fastest-growing software ecosystems with the qualities that have made IBM systems the foundation for how businesses run today.
- u1hcw9nx
Not explained in the article:
Every single physical core on the chip decodes and executes both s390x and Arm AArch64 instructions, dynamically switching between the two ISA modes and convert them into micro ops. Mode switching is hypervisor-driven.
And those chips are fast. 5.7 Ghz 2nm node.
For who: When you need to run Linux programs on high security, mission critical environment. Others should not care.
- userbinator
The article is quite short on details but I wonder if this is an ARM core that can also execute IBM Z, or the other way around; in other words, which ISA does it execute its first instruction at the reset vector? In that past I've worked on a conceptual design for an "x86+" CPU, which would start as a regular x86 but then be able to execute code of other architectures like ARM, MIPS, PPC, etc. isolated in their own code segments, similar to how V86 mode works.
- skissane
20 years ago, IBM had their eCLipz initiative to unify z and POWER. What actually shipped was two different CPUs sharing some design, but some of the media reports on it made it sound like it may have originally been more ambitious-one CPU with two instruction sets.
If that’s what it was, looks like they finally shipped it, just replacing POWER with ARM
- _joel
"AI acceleration for in transaction fraud detection", sounds interesting but also quite risky. Is it just a generic inference accelerator or something more exotic?
- classichasclass
This feels like a baby step towards Arm being able to emulate z/Arch workloads, maybe with a bit of secret sauce for certain specific operations, which doesn't seem very much like IBM.
- avhception
Huh. ARM instead of ppc64le?
- christkv
Is this like the Transmeta processors doing code translation in hardware?
- SeifHashish
why is IBM moving forward that way