Gemini 3.1 Pro Preview vs GPT-5 Codex
A side-by-side comparison of two multimodal models — real specs, pricing, strengths and weaknesses, and a clear verdict on which to choose. Kept current by our agents.
Quick verdict: which should you choose?
Choose Gemini 3.1 Pro Preview if you need
- ✓Need native audio, video, image, and text integration for multimodal analysis
- ✓Require up to 1M token context for large-scale document processing
- ✓Prioritize the highest intelligence index (46.5) on complex tasks
- ✓Value strong cross-modality integration over raw speed
Choose GPT-5 Codex if you need
- ✓Need faster output speed (169.49 t/s) for high-volume generation
- ✓Want lower cost at $10 per 1M tokens
- ✓Focus on coding specialization with unified text and image reasoning
- ✓Operate within a 400K context limit without needing audio or video
Verdict
Gemini 3.1 Pro Preview leads with a higher intelligence index (46.5 vs 36.1), a 1M-token context window, and native support for audio/video alongside text and images, making it stronger for complex multimodal document tasks. GPT-5 Codex counters with faster output (169.49 t/s vs 128.71 t/s) and lower price ($10 vs $12 per 1M tokens) plus coding specialization. The preview status of Gemini introduces potential inconsistency risks not noted for GPT-5 Codex.
Gemini 3.1 Pro Preview vs GPT-5 Codex: side by side
| Spec | Gemini 3.1 Pro Preview | GPT-5 Codex | Winner |
|---|---|---|---|
| Intelligence | 46.5 | 36.1 | Gemini 3.1 Pro Preview |
| Output speed | 129 t/s | 169 t/s | GPT-5 Codex |
| Output price | $12.00/1M | $10.00/1M | GPT-5 Codex |
| Context | 1049K | 400K | Gemini 3.1 Pro Preview |
| Params | — | — | Tie |
| Provider | OpenAI | Tie |
Detailed analysis
Intelligence
Winner: Gemini 3.1 Pro PreviewGemini 3.1 Pro Preview scores 46.5 on the intelligence index compared to 36.1 for GPT-5 Codex. This gap favors Gemini for complex multimodal reasoning. Both models are proprietary with unspecified parameter counts.
Speed
Winner: GPT-5 CodexGPT-5 Codex delivers 169.49 tokens per second versus 128.71 for Gemini 3.1 Pro Preview. The speed advantage holds for high-throughput text and image tasks. Both face high resource demands at maximum context lengths.
Context & Modalities
Winner: Gemini 3.1 Pro PreviewGemini supports a 1,048,576-token context and native audio, image, video, and text inputs. GPT-5 Codex is limited to 400,000 tokens and text plus static images only. Gemini's larger window suits large-scale document analysis.
Pricing
Winner: GPT-5 CodexGPT-5 Codex costs $10 per million output tokens while Gemini 3.1 Pro Preview costs $12. Both are proprietary models from major providers. Price difference is modest but favors GPT-5 Codex on volume workloads.
Gemini 3.1 Pro Preview
Pros
- +Handles up to 1M token contexts
- +Native support for audio, image, video, and text
- +Strong integration of multiple modalities
Cons
- –Preview model may show inconsistent outputs
- –High resource use with maximum context
- –Requires verification on complex tasks
GPT-5 Codex
Pros
- +Handles extremely large inputs effectively
- +Strong coding specialization
- +Unified text and image reasoning
Cons
- –High resource demands with maximum context
- –Limited to text and static images
- –Potential coherence loss in very long outputs
Summary: Gemini 3.1 Pro Preview vs GPT-5 Codex
Choose Gemini 3.1 Pro Preview for maximum context, full multimodal coverage, and higher intelligence scores. Select GPT-5 Codex when speed, lower price, and coding focus matter most within its modality limits. The models trade off breadth and depth against efficiency.
Frequently asked questions
Gemini 3.1 Pro Preview is stronger for multimodal tasks due to native audio/video support, 1M context, and higher intelligence index, while GPT-5 Codex is limited to text and static images.