Source: arstechnica.com/google/2026/11/google-rolls-out-gemini-4-hydrogen-finally-replacing-3-8-flash
Google positions Hydrogen as the faster, more economical successor to the Flash models that most of its users rely on. It runs at one of four thinking levels: low, medium, high, and the new xhigh. Google says even high mode is 2.5 times faster than Flash 3.8 and cuts fabricated claims by more than five times, according to its own analysis.
Google also reports that Hydrogen more than triples Flash 3.8's score on Terminal-Bench, and that its xhigh mode scores 54 on the Artificial Analysis Intelligence Index against 50 for Argon. Hydrogen is also being integrated into Google Search, where AI Overviews and AI Mode will get more visual elements. Access is staged: it is live for AI Pro and Ultra subscribers, while AI Plus and free users remain on Gemini 3.5 Flash-Lite.
API pricing is $1.50 per million input tokens and $7.50 per million output tokens, the same as Flash 3.8. Argon and Carbon currently cost $2 and $10 and will rise to $4 and $20 starting next month.
Why it matters if you build agents
Developers calling the API can move to Hydrogen at Flash 3.8's price for faster generation of simpler code and test runs. Google still positions Argon and Carbon as the better choice for long-horizon tasks and security work.
Argon and Carbon prices are set to double next month, so agent budgets built on them should be rechecked.
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