AMD Unveils Instinct MI455X GPU and Helios Rack-Scale AI System to Challenge Nvidia

What happened

On July 23, 2026, AMD officially unveiled the Instinct MI455X GPU and the Helios rack-scale system at its Advancing AI 2026 event — positioning both as direct challengers to Nvidia NVL144 with Vera Rubin GPUs.

Context and impact

The MI455X is built on CDNA 5 architecture (12 chiplets on TSMC N2) with 432GB HBM4 memory and 23.3 TB/s bandwidth. The Helios rack integrates 72 MI455X GPUs with AMD EPYC Venice CPUs and Pensando networking, delivering 2.9 ExaFLOPS (FP4) at $5–5.5M per rack. Confirmed customers include OpenAI, Meta, Anthropic, Microsoft, and Oracle — Anthropic confirmed up to 2 gigawatts of planned deployment.

Details

• 320 billion transistors across 12 TSMC N2 chiplets, CDNA 5 architecture
• 432GB HBM4 memory, 23.3 TB/s bandwidth per GPU
• 40.26 PFLOPS MXFP4 compute per GPU
• Helios rack (72 × MI455X): 2.9 ExaFLOPS FP4, 1.7 PB/s aggregate bandwidth
• Price: $5–5.5 million per rack
• Shipments begin Q3 2026, ramping Q4 2026 – H1 2027
• Roadmap: MI500 (2027), MI600 (2028)