OpenAI: GPT-5 Pro vs Google: Gemini 3 Flash Preview

Compare these two models side-by-side to help you make the best choice for your needs

OpenAI: GPT-5 Pro

Premium

Description

GPT-5 Pro is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. It is optimized for complex tasks that require step-by-step reasoning, instruction following, and accuracy in high-stakes use cases. It supports test-time routing features and advanced prompt understanding, including user-specified intent like "think hard about this." Improvements include reductions in hallucination, sycophancy, and better performance in coding, writing, and health-related tasks.

Strengths

  • Multimodal understanding with text and image support
  • Large context window (400k tokens)

Best For

Image and document understanding

Google: Gemini 3 Flash Preview

Description

Gemini 3 Flash Preview is a high speed, high value thinking model designed for agentic workflows, multi turn chat, and coding assistance. It delivers near Pro level reasoning and tool use performance with substantially lower latency than larger Gemini variants, making it well suited for interactive development, long running agent loops, and collaborative coding tasks. Compared to Gemini 2.5 Flash, it provides broad quality improvements across reasoning, multimodal understanding, and reliability. The model supports a 1M token context window and multimodal inputs including text, images, audio, video, and PDFs, with text output. It includes configurable reasoning via thinking levels (minimal, low, medium, high), structured output, tool use, and automatic context caching. Gemini 3 Flash Preview is optimized for users who want strong reasoning and agentic behavior without the cost or latency of full scale frontier models.

Strengths

  • Multimodal understanding with text and image support
  • Large context window (1049k tokens)

Best For

Image and document understanding

FeatureOpenAI: GPT-5 ProGoogle: Gemini 3 Flash Preview
ProviderOpenRouterOpenRouter
Context Length400,000 tokens1,048,576 tokens
Input Price$15.00/M$0.500/M
Output Price$120.00/M$3.00/M
Vision SupportYesYes
PremiumYesNo
Capabilities
TextVision
TextVisionFast