Claude Opus 4.8 (Fast) vs GPT-5.1
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.
Claude Opus 4.8 (Fast) vs GPT-5.1: side by side
| Spec | Claude Opus 4.8 (Fast) | GPT-5.1 | Winner |
|---|---|---|---|
| Intelligence | 61.4 | 27.4 | Claude Opus 4.8 (Fast) |
| Output speed | 62 t/s | 116 t/s | GPT-5.1 |
| Output price | $50.00/1M | $10.00/1M | GPT-5.1 |
| Context | 1000K | 400K | Claude Opus 4.8 (Fast) |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | Anthropic | OpenAI | Tie |
Claude Opus 4.8 (Fast)
Pros
- +Strong safety alignment
- +Nuanced and careful reasoning
- +Effective large-context handling
- +High-quality writing and analysis
Cons
- –Can be overly cautious on edge cases
- –Multimodal performance varies with image clarity
- –Fast mode may trade some depth for speed
GPT-5.1
Pros
- +Very large context window
- +Native support for images, text, and files
- +Strong multimodal integration
Cons
- –No audio or video modalities
- –Performance details unverified beyond specs
- –Potential latency with maximum context
Frequently asked questions
It depends on your needs. Claude Opus 4.8 (Fast) and GPT-5.1 are both multimodal models; the comparison table above shows where each one leads on the metrics that matter. See the verdict for a recommendation.