Choose Gemma 4 31B when you want the strongest open-weight Gemma 4 experience and your task quality matters more than minimal hardware cost. It is the model size to consider for deeper reasoning, larger structured outputs, and demanding assistant-style workflows.
31B is not the “start here” option for most local users. Treat it as a deliberate deployment decision and check Gemma 4 requirements before chasing the largest model first.