Hot Chips 2026: IBM’s first dual-ISA core natively executes ARM and z/Architecture in the same core; all cores run at 5.7 GHz base frequency — next-gen mainframe AI processor is built on 2nm node with 11 cores

IBM‘s next-gen AI processor is the first time it has supported dual ISA execution natively within the same core. Born out of a collaboration between IBM and Arm that was announced in April, the chip is designed to bring the software support available across the Arm ecosystem to IBM’s mainframes, allowing businesses to unify deployment rather than relying on separate Arm/x86 servers and z/Architecture mainframes for different purposes.

The approach here isn’t a heterogeneous CPU with separate Arm cores packaged on the same chip; IBM has built a core that can execute either z/Architecture or AArch64 instructions, and can switch between them dynamically “within nanoseconds,” according to the company. During the Hot Chips 2026 reveal, IBM says it believes this is the first processor to treat both ISAs as “first-class citizens.”