xAI brings Colossus 2 online, billed as the first gigawatt-scale AI training cluster
In January 2026 xAI said its Colossus 2 supercomputer in Memphis came online as the first AI training cluster drawing ~1 GW, and announced a third building to take the site toward 2 GW (~555,000 Nvidia GPUs, ~$18B); satellite analysis reported by Tom's Hardware disputed that it had reached 1 GW of capacity.
Key facts
- Claimed ~1 GW power draw in January 2026 (exact date uncertain; mid-January reports)
- Plan: expand Memphis site toward 2 GW with a third building; ~555,000 Nvidia GPUs purchased for ~$18B (reports)
- Roadmap cited 1.5 GW by April and full operation by June 2026
- Tom's Hardware: satellite imagery suggested only ~350 MW of cooling capacity at the time
What happened
xAI claimed the gigawatt milestone ahead of OpenAI's Stargate Abilene (1.2 GW planned). Claims are contested.
Why it matters
Gigawatt-class single-site clusters define the 2026 frontier-training scale; confidence low on exact capacity and date.
Changelog
- 2026-09-29: created
Sources (3)
- pressSemiAnalysis: xAI's Colossus 2 — first gigawatt datacenter
- pressTeslarati: xAI brings 1GW Colossus 2 online
- pressTom's Hardware: Colossus 2 is nowhere near 1 GW, satellite imagery suggests
id: 2026-01-01-xai-colossus-2-gigawatt · updated 2026-09-29 · open in the interactive timeline