IBM LinuxONE
IBM LinuxONE is a line of IBM mainframe servers built on the s390x architecture and optimized exclusively for Linux. It shares the same hardware foundation (the IBM Telum II processor) as the IBM Z family but is positioned for Linux, open-source, hybrid-cloud and AI workloads. The latest, fifth generation is IBM LinuxONE 5 (Emperor 5), announced on 6 May 2025.
LinuxONE 5 is powered by the IBM Telum II processor — a chip with eight cores clocked at 5.5 GHz, a 40% larger cache (a 2.88 GB L4 cache) and a second-generation integrated on-chip AI accelerator for real-time inferencing. The system (machine type 9175) scales up to 64 TB of memory. According to IBM, the platform processes up to 5 million inference operations per second at a response time of under 1 ms.
Generative-AI performance can be extended with IBM Spyre Accelerator cards (32 cores per card, up to 8 cards, i.e. 256 acceleration cores per server), available from Q4 2025. LinuxONE 5 delivers 99.999999% availability (eight nines), confidential computing, a hardware security module and post-quantum cryptography based on NIST-standardized algorithms. Certified operating systems are Red Hat Enterprise Linux, SUSE Linux Enterprise Server and Ubuntu; the platform integrates with Red Hat OpenShift. LinuxONE 5 is available in the Emperor 5, Rockhopper 5 and LinuxONE 5 Express variants (from USD 165,000).
Classification
Mainframe · serves as: AI Inference, AI acceleration, Compute.
Which group IBM LinuxONE belongs to and how it is built
This subcategory covers complete mainframe systems: large-scale enterprise-class servers engineered for continuous operation, maximum reliability and security, and processing of very high transaction volumes. Modern mainframes integrate AI acceleration (on-chip and PCIe cards), advanced cryptography and virtualization, running operating systems such as z/OS and Linux. They are used in banking, insurance, government and other sectors with stringent SLA requirements.
A component type describing complete mainframe systems. These are centralized, large-scale computing platforms designed for mission-critical production workloads, featuring hardware redundancy, advanced virtualization, AI acceleration and hardware encryption. They offer very high availability (many "nines"), scalable processor and memory counts, and support for dedicated operating systems (e.g. z/OS) alongside Linux.
Technical specification
IBM LinuxONE Emperor 5 model.
Shared with the IBM Z family.
40% larger cache vs the previous generation.
40% larger cache vs the previous generation.
Relations
Other hardware parts related to IBM LinuxONE
Enterprise-class IBM mainframe (machine type 9175) with the 5.5 GHz IBM Telum II processor, up to 208 cores and 64 TB memory, engineered for in-transaction AI inference.
IBM's dedicated AI accelerator system-on-a-chip on a PCIe card for generative and agentic AI inference on IBM Z (z17), LinuxONE 5 mainframes and Power11 servers.