xAI Colossus 2 Hits 1.5 Gigawatts in April — 850K GPUs, World's Largest Training Cluster
Elon Musk / SemiAnalysis / Tom's Hardwarevia @elonmusk·medium signal
Elon Musk confirmed xAI's Colossus 2 upgraded to 1.5GW in April, adding ~250K GPUs to reach 850K total. It's the world's first gigawatt-scale AI training cluster, activated mid-January at 1GW. A third building ('MACROHARDRR') is expanding capacity toward 2GW. Grok 5 is reportedly still training on the cluster. Tom's Hardware analysis of satellite imagery previously questioned whether the facility had reached 1GW cooling capacity — the 1.5GW claim will face similar scrutiny.