Anthropic Says Claude Mythos Ported Claude to AMD GPUs in About Three Days

Anthropic said Claude Mythos helped port Claude to AMD’s MI355X GPUs in about three days, ahead of a separate plan for Anthropic to use up to two gigawatts of AMD’s MI450-series GPUs.

The test dates to July 2026. Anthropic’s account says an engineer connected Claude to the MI355X hardware and asked it to get started. Mythos handled most of the software migration and performance tuning, with minimal human help. Anthropic said performance improved without ongoing human intervention.

The MI355X is based on AMD’s CDNA 4 architecture. It has 288 GB of HBM3E memory and 8 TB/s of bandwidth, with peak performance of up to 10 PFLOPS.

AMD and Anthropic announced a separate partnership July 22. Anthropic committed to using up to two gigawatts of AMD Instinct MI450-series GPUs in AMD Helios rack-scale systems, with deployment planned for the first half of 2027. The agreement also includes plans for Claude to help improve ROCm, AMD’s software for running AI workloads on its chips. AMD pledged an equity investment of up to $5 billion in Anthropic.

Claude Mythos 5.2 debuted Nov. 9, with access restricted to vetted cybersecurity and life sciences programs, as detailed in the Claude Mythos 5.2 release coverage.