Gemini 2.5 Pro vs Gemma 4 31B

Pick Gemma 4 31B if you want the stronger benchmark profile. Gemini 2.5 Pro only becomes the better choice if coding is the priority or you need the larger 1M context window.

Gemma 4 31B finishes one point ahead on BenchLM's provisional leaderboard, 64 to 63. That is enough to call, but not enough to treat as a blowout. This matchup comes down to a few meaningful edges rather than one model dominating the board.

Gemma 4 31B's sharpest advantage is in knowledge, where it averages 61.3 against 40.8. The single biggest benchmark swing on the page is HLE, 18.8% to 26.5%. Gemini 2.5 Pro does hit back in coding, so the answer changes if that is the part of the workload you care about most.

Gemini 2.5 Pro is also the more expensive model on tokens at $1.25 input / $10.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Gemma 4 31B. That is roughly Infinityx on output cost alone. Gemma 4 31B is the reasoning model in the pair, while Gemini 2.5 Pro is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Gemini 2.5 Pro gives you the larger context window at 1M, compared with 256K for Gemma 4 31B.