Gemma 3 27B vs GPT-5 Pro

Gemma 3 27B

Google DeepMind

Gemma 3 27B is a 27-billion-parameter open-weight model from Google DeepMind, released in March 2025 alongside the Gemma 3 12B as the higher-capability variant in the series, built with native vision-language support for text and image inputs across a 128K token context window. Among the Gemma 3 releases, the 27B delivered the strongest results on instruction-following and knowledge-intensive reasoning tasks, making it the preferred option for developers needing greater accuracy from a self-hostable model. Its open-weight availability under a permissive license made it a common starting point for vision-language fine-tuning projects.

GPT-5 Pro

OpenAI

GPT-5 Pro is an extended-reasoning variant from the GPT-5 family that applies more compute per response for deeper, more thorough answers on complex problems. It features the same 400K token context window and multimodal capabilities as GPT-5, with additional reasoning depth suited to research-grade analysis, advanced coding, and tasks requiring comprehensive, accurate outputs.