When Google DeepMind quietly flipped the switch on Gemini 2.5 Deep Think, it wasn’t just another toggle in the Gemini app. The same enhanced-reasoning mode had already notched a gold-medal-level score at the 2025 International Mathematical Olympiad (IMO)—solving five of six notoriously brutal problems and tying the human cutoff for gold. That feat put DeepMind shoulder-to-shoulder with OpenAI’s own experimental “gold-IMO” model, announced the very same week .
What makes the IMO special?
Founded in 1959, the IMO pits six pre-university prodigies from each country against six problems spanning algebra, geometry, number theory, and combinatorics. Every question is worth seven points, so 42 is perfection; a score of 35 secured this year’s gold cutoff. DeepMind’s best 2024 system managed silver, but needed more time than the four-and-a-half hours allotted to humans. In 2025, Deep Think achieved the same result within the human time window, using only plain-language prompts instead of formal proof assistants .
Under the hood: parallel minds at work
Deep Think is Gemini 2.5 Pro running in a multi-agent “parallel thinking” mode. Instead of one chain-of-thought, it spins up dozens, scores them against intermediate goals, and fuses the strongest ideas into a final answer. Google says the approach boosts benchmark scores for math, logic, and coding, at the cost of far longer inference times .
A field test from the transcript
In the YouTube walkthrough, the host pastes a 2025 IMO geometry problem into Deep Think. The clock ticks 16 minutes before the first full token arrives—but the model nails the official solution, listing the only valid values of k as 0, 1, 3. A second experiment on an AIME-25 algebra question takes 13 minutes yet again lands the correct answer (204) with detailed derivations. The lesson: breakthroughs come after a coffee break, not in real time.
Beyond math: voxel temples and half-baked Angry Birds
Deep Think’s slow-burn genius extends to generative tasks. Asked to script a colorful 3D “Sala Thai” pavilion in Three.js, the model architected a fully navigable voxel scene—complete with stylized roof eaves—on the first pass. A tougher challenge—re-creating Angry Birds in Pygame—showed its iterative potential: the first build lacked obstacles, but a follow-up prompt produced pigs, wood, glass, and workable physics. Still, each refinement added another ten-plus minutes to the wait.
When speed matters more than brilliance
Because Deep Think withholds partial streams until it has weighed all candidate thoughts, users stare at a blank screen for up to ten minutes. Google engineers admit the mode “isn’t practical for everyday coding” unless you fire a prompt and walk away—then return to review the answer or receive a push notification. For everyday tasks, plain Gemini 2.5 Pro or Flash-Lite may offer better latency-to-value ratios.
How to try it—and what’s next
Deep Think is already live for Gemini Ultra subscribers inside the consumer app, and Google says an API endpoint will roll out in the “next few weeks” to AI Studio and Vertex AI . Once that lands, developers can add a “deep-think” flag to long-form reasoning jobs—think automated theorem proving, contract analysis, or multi-step coding agents.
Bottom line: Gemini Deep Think proves massive parallel reflection can push public models into Olympiad territory, but it also shows there’s no free lunch—each extra IQ point costs time and compute. The next frontier won’t just be smarter LLMs; it will be orchestration layers that decide when a 16-minute think-tank is worth the wait and when a quick, cheaper model will do.
