Google Gemini 3 Flash Review — Frontier Reasoning at Mid-Tier Speed, Default Model in Gemini App

Gemini 3 Flash launched December 17, 2025 as the immediate default model in the Gemini app and AI Mode in Google Search. It scores 90.4% on GPQA Diamond, 71 on the Artificial Analysis Intelligence Index, and reaches ~200 tokens/second — positioned between Flash-Lite and Pro on price ($0.50/$3.00/M) and capability. We review benchmarks, the hallucination anomaly, thinking modes, multimodal support, and pricing against the Gemini 3 family.