Gemini 3.5 Flash vs GPT-5.1-Codex-Max
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 3.5 Flash if you need
- ✓Choose GPT-5.1-Codex-Max if you need strong coding focus with text and image inputs.
- ✓Choose GPT-5.1-Codex-Max if you need handling of very large 400k-token contexts for complex technical workflows.
- ✓Choose GPT-5.1-Codex-Max if you need a model limited to text and image modalities without other media types.
Choose GPT-5.1-Codex-Max if you need
- ✓Choose Gemini 3.5 Flash if you need output speed of 154.62 t/s and $9/1M pricing.
- ✓Choose Gemini 3.5 Flash if you need support for text, image, video, and audio tasks.
- ✓Choose Gemini 3.5 Flash if you need a 1,048,576-token context window.
- ✓Choose Gemini 3.5 Flash if you need high speed and efficiency with versatile multimodal integration.
Verdict
Gemini 3.5 Flash leads in speed, price, context size, and modality breadth while GPT-5.1-Codex-Max leads for coding-focused text-and-image workflows that need reliable handling of 400k-token technical inputs. GPT-5.1-Codex-Max has no reported speed or intelligence metrics, so direct performance comparison is not possible from the given facts. Gemini 3.5 Flash trades depth on complex tasks for its measured efficiency advantages.
Gemini 3.5 Flash vs GPT-5.1-Codex-Max: side by side
| Spec | Gemini 3.5 Flash | GPT-5.1-Codex-Max | Winner |
|---|---|---|---|
| Intelligence | 45.4 | — | Tie |
| Output speed | 155 t/s | — | Tie |
| Output price | $9.00/1M | $10.00/1M | Gemini 3.5 Flash |
| Context | 1049K | 400K | Gemini 3.5 Flash |
| Params | — | — | Tie |
| Provider | OpenAI | Tie |
Detailed analysis
Context Window
Winner: Gemini 3.5 FlashGemini 3.5 Flash provides a 1,048,576-token context while GPT-5.1-Codex-Max offers 400,000 tokens. Both models support large contexts, but Gemini's window is more than double the size according to the stated figures.
Pricing
Winner: Gemini 3.5 FlashGemini 3.5 Flash is listed at $9 per million tokens compared with GPT-5.1-Codex-Max at $10 per million tokens. The one-dollar difference favors Gemini on cost for equivalent output volume.
Modalities
Winner: Gemini 3.5 FlashGemini 3.5 Flash supports text, image, video, and audio while GPT-5.1-Codex-Max is limited to text and image. GPT-5.1-Codex-Max therefore cannot process video or audio inputs according to the given descriptions.
Coding & Technical Workflows
Winner: GPT-5.1-Codex-MaxGPT-5.1-Codex-Max lists a strong coding focus and suitability for complex technical workflows with text and image. Gemini 3.5 Flash does not list coding specialization and notes it trades depth for speed on complex tasks.
Gemini 3.5 Flash
Pros
- +High speed and efficiency
- +Strong multimodal integration
- +Large context window support
Cons
- –Trades depth for speed on complex tasks
- –Variable performance on specialized domains
- –Context utilization depends on task
GPT-5.1-Codex-Max
Pros
- +Handles very large contexts
- +Strong coding focus
- +Combines text and image inputs
Cons
- –Limited to text and image modalities
- –High resource demands for large contexts
- –No support for other media types
Summary: Gemini 3.5 Flash vs GPT-5.1-Codex-Max
Select Gemini 3.5 Flash when speed, lower price, larger context, and video/audio support matter most. Select GPT-5.1-Codex-Max when the priority is coding-oriented text-and-image work within a 400k-token window. The facts provide no intelligence or speed numbers for GPT-5.1-Codex-Max, limiting direct head-to-head claims.
Frequently asked questions
Gemini 3.5 Flash reports 154.62 tokens per second; no speed figure is given for GPT-5.1-Codex-Max.