Microsoft AI leveraged Ray to train its new 1-trillion parameter MAI-Thinking-1 Mixture-of-Experts reasoning model

From: Microsoft AI leveraged Ray to train its new 1-trillion parameter MAI-Thinking-1 Mixture-of-Experts reasoning model

ray@raydistributed·8hQuote tweet

Congratulations to the Microsoft AI team on MAI-Thinking-1! Exciting to see Ray used in multiple parts of frontier-model development. - Fast pre-training recovery via in-job restarts with hot standbys - Async RL orchestration (managing learners, inference servers, rollout workers, and routers, each with distinct placement and fault-tolerance needs) - A two-pool Ray cluster for building and grading SWE environments on 30K CPU cores

Microsoft AI@MicrosoftAI·12hView on

MAI-Thinking-1 is our first in-house reasoning model developed from scratch that is competitive with models of similar size on STEM reasoning and coding tasks. 35B active/1T total MOE. 💻Coding: 52.8% on SWE Bench Pro competitive with Opus 4.6 🧐 Reasoning: 97% on AIME 25 🤝Preferred to Sonnet 4.6 on blind side-by-side tests

Table comparing MAI‑Thinking‑1 with other models on STEM and coding benchmarks, showing performance scores across multiple tests.

View on