Gemini 3.1 Pro Preview vs Gemini 3.5 Flash

Gemini 3.1 Pro Preview is Google’s frontier reasoning model, offering stronger software engineering performance, more dependable agent behavior, and more efficient token use across demanding workflows. Built on the multimodal foundation of the Gemini 3 series, it delivers high-accuracy reasoning across text, images, video, audio, and code, supported by a 1M-token context window. The 3.1 update brings clear improvements on SWE benchmarks and in real-world coding scenarios, along with more robust autonomous task execution in structured areas like finance and spreadsheet-driven workflows. Created for advanced development and agentic systems, Gemini 3.1 Pro Preview enhances long-horizon stability and tool coordination while further improving token efficiency. It also adds a new medium thinking mode to better balance cost, speed, and quality. The model shines in agentic coding, structured planning, multimodal analysis, and workflow automation—making it a strong fit for autonomous agents, financial modeling, spreadsheet automation, and other high-context enterprise tasks.

Gemini 3.5 Flash is Google's high-efficiency multimodal model, bringing near-Pro level coding and reasoning at Flash-tier cost and speed. It is highly optimized for coding proficiency and parallel agentic execution loops, supporting text, image, video, audio, and PDF inputs.