IBM's new chip runs Arm and Z workloads simultaneously
What's the story
IBM has unveiled a groundbreaking chip at the annual Hot Chips conference, marking a major shift in mainframe architecture. This next-gen processor is capable of running both IBM's own instruction set and Arm's on the same cores, switching between them in nanoseconds. The dual-architecture mainframe processor will power future generations of IBM Z and LinuxONE systems.
Technological leap
Mainframe's role in AI-driven world
The new chip will allow businesses to run a wide range of Arm-native Linux software, including AI frameworks. These tools are increasingly becoming essential for modern infrastructure.
The move also answers a long-standing question about the mainframe's role in an AI-driven world dominated by other people's silicon.
"We're really excited about being what I would consider one of the most powerful commercially available processors that'll be dual architecture," said Tina Tarquinio, IBM Z and LinuxONE Chief Product Officer.
Design innovation
Every core on the chip is bilingual
Instead of adding standalone Arm cores to its processor, IBM has designed every core on the chip to be bilingual.
"On this chip are 11 cores, and each core can dynamically switch back and forth between Arm software mode and traditional Z software mode," said Christian Jacobi, IBM Fellow and CTO of IBM Systems Development.
This design lets mission-critical enterprise software run alongside a broader ecosystem of Arm applications on the same chip.
Technical details
The chip uses open-source KVM hypervisor
The chip uses the open-source KVM hypervisor, allowing businesses to run Arm64 Linux virtual machines and Linux on Z virtual machines simultaneously.
As the hypervisor dispatches each virtual machine onto a physical core, it switches into the corresponding mode with virtually no performance penalty.
Traditional z/OS workloads run in a separate partition on the same chip, enabling different systems to share the same silicon and memory fabric while maintaining reliability guarantees.
Performance specs
Chip runs at extremely fast speeds
The chip runs its 11 high-performance cores at a base frequency above 5.7GHz, which is extremely fast by industry standards.
It also features on-chip AI inference accelerators for in-transaction fraud detection and a dedicated data processing unit for I/O acceleration.
Full systems will scale to hundreds of cores and tens of terabytes of memory, showing that mainframe technology is still very much modern and leading-edge.
Compatibility promise
Ensuring binary compatibility with existing applications
IBM's s390x architecture processes a huge share of the world's mission-critical transactions. However, enterprise software was built for x86 and Arm.
"No matter how great our ecosystem team is, we would never be able to work with all of them and port them all," said Tarquinio.
The new chip promises that Arm Linux binaries will run unmodified, ensuring 100% binary compatibility with existing applications.
AI integration
Next-gen Spyre AI accelerator previewed at Hot Chips
IBM is also previewing the next generation of its Spyre AI accelerator at Hot Chips. The new Spyre will ship with high-bandwidth memory to support large language models for agentic workflows and business workflows.
As AI scales, more of the computing landscape is converging on Arm. Bringing Arm compute and its software ecosystem to these platforms will extend that momentum into mission-critical enterprise infrastructure to give organizations greater choice in how they deploy AI.
Product roadmap
Chip will debut in successor to z17 mainframe
The chip will debut in the successor to the z17, which shipped in the second quarter of 2025.
However, Tarquinio assured that this program is well beyond the concept stage.
"It's more than being on the drawing board. We're full steam ahead on the whole system," she said, adding that IBM will share more information leading up to launch.