Google's Gemini 4 Hydrogen outscores the bigger Argon just four weeks after its launch

Google released Gemini 4 Hydrogen, a fast general-purpose model for developers and everyday users that scores 51 on the Artificial Analysis Intelligence Index at its default "high" thinking level (54 at the new "xhigh" tier), beating the larger Gemini 4 Argon's 50. It has a one-million-token input and output window and costs $1.50 per million input tokens and $7.50 per million output tokens, with Google reporting a jump from 18.2% to 57% on Terminal-Bench 4.1 versus Gemini 3.8 Flash. Artificial Analysis found Hydrogen hallucinates only 8% of the time but lags on agentic terminal work, scoring 54% on Terminal-Bench 4.0 and 50% on Terminal-Bench-Science 0.1.