Microsoft Maia 300 vs Nvidia Rubin: specs compared, no clear winner
Microsoft unveiled Maia 300 on Oct. 12, 2026, and plans to expand its Azure Maia infrastructure to multi-gigawatt deployments starting in 2027, positioning the chip as its primary AI inference engine. Maia 300 pairs 288 GB of HBM4 and 18 TB/s peak bandwidth per accelerator at 950W, with 96 accelerators per rack totaling 27.6 TB of HBM4 and 167 kW; Nvidia's Rubin NVL72 lists 288 GB HBM4 and up to 22 TB/s per GPU, with 72 GPUs and 20.7 TB aggregate HBM4 per rack. Their efficiency claims use different baselines and no independent, workload-matched test exists: Microsoft says Maia 300 delivers 40% more tokens per megawatt than unnamed leading GPU systems, while Nvidia projects Rubin NVL72 at up to 10x the tokens per megawatt of GB200 NVL72, so neither can be declared faster.
It shows the inference-hardware race is still argued with vendor-chosen baselines, so buyers should wait for workload-matched measurements.