IBM is building a dual-architecture mainframe chip that will run Arm and Z software on the same cores

IBM is developing a mainframe chip capable of running both Arm and Z software simultaneously on the same cores, as showcased at Hot Chips 2026. This dual-architecture chip is expected to utilize 11 IBM Z cores built on a 2-nanometer process, with each core able to execute both z/Architecture and AArch64 instructions concurrently.

The processor will include specialized accelerators for AI inference, data processing, compression, cryptography, and sorting. With a large cache system, including a 36 MB private L2 cache, 432 MB virtual L3 cache, and up to 3.5 GB of virtual L4 cache, the chip is designed to keep latency low for large databases and transaction-heavy workloads.

IBM's goal is to combine the reach of the Arm software ecosystem with the scalability, security, and high-availability features of its existing mainframe systems. The company expects the chip to arrive in 2028, potentially becoming a part of the future z18 mainframe family. This move could help IBM maintain its relevance in the mainframe market, which remains critical for many large organizations, particularly in financial services, while also catering to the growing demand for Linux and AI workloads.