AMD Unveils Instinct MI455X AI Accelerator and Helios Rack-Scale Architecture to Compete with Nvidia
At its Advancing AI 2026 event, AMD revealed the Instinct MI455X GPU, its most advanced AI accelerator built with 320 billion transistors using TSMC's 2N GAA process and CoWoS-L packaging. The chip features CDNA 5 architecture with 256 Work Group Processors, a wavefront size of 32, and up to 4x performance improvement in lower-precision formats like MXFP4 and MXFP8 compared to the previous MI355X. AMD also introduced the Helios rack-scale architecture, linking 72 MI455X GPUs into a coherent system to rival Nvidia's NVL72 design. On paper, the MI455X outperforms Nvidia's upcoming Rubin GPU in several peak FLOPS metrics. AMD announced key customer wins with Microsoft and Anthropic. However, the company acknowledged that real-world performance may be lower than theoretical peaks, emphasizing the need for software optimization.
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