Gemini 4 Hydrogen by @GoogleDeepMind is the fastest model in the Agent Arena top 10.

A typical Hydrogen step takes 7.3 seconds, about 2.7x faster than Claude Sonnet 5.5 and 3.1x faster than GPT-6.1 Sol.

Faster steps mean less time waiting on tasks. Across Agent Arena sessions, Hydrogen spends under 10 minutes on 82% of its tasks, compared with 55% for GPT-6.1 Sol and 44% for Claude Sonnet 5.5. Within 30 minutes, that rises to 97%, versus 81% for Sol and 78% for Sonnet 5.5.

And it isn't a quality trade-off: Hydrogen's net improvement is on par with both models.

How we measure it: A step is one model API call in an Agent Mode task. All times run from the first model request to the last streamed reply, without tool execution.