GPT-5.1-Codex-Mini vs Grok 4.20
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 GPT-5.1-Codex-Mini if you need
- ✓faster output at 214.62 t/s for time-sensitive coding sessions
- ✓lower cost at $2 per 1M tokens on extended technical workflows
- ✓strong coding specialization with native image and text support
- ✓400k context sufficient for large but not extreme codebases
Choose Grok 4.20 if you need
- ✓highest intelligence score (49.3) on complex multimodal tasks
- ✓up to 2M token context for massive file and document sets
- ✓native text, image, and file inputs in one model
- ✓larger context window when input scale is the primary constraint
Verdict
Grok 4.20 leads on raw intelligence (49.3 vs 38.6) and context capacity (2M vs 400k tokens), making it stronger for very large multimodal inputs. GPT-5.1-Codex-Mini wins on speed (214.62 t/s vs 168.03 t/s), lower price ($2 vs $2.5 per 1M), and explicit coding specialization with image+text support. The choice hinges on whether maximum context and intelligence or faster, cheaper coding workflows matter more.
GPT-5.1-Codex-Mini vs Grok 4.20: side by side
| Spec | GPT-5.1-Codex-Mini | Grok 4.20 | Winner |
|---|---|---|---|
| Intelligence | 38.6 | 49.3 | Grok 4.20 |
| Output speed | 215 t/s | 168 t/s | GPT-5.1-Codex-Mini |
| Output price | $2.00/1M | $2.50/1M | GPT-5.1-Codex-Mini |
| Context | 400K | 2000K | Grok 4.20 |
| Params | — | — | Tie |
| Type | Proprietary | Proprietary | Tie |
| Provider | OpenAI | xAI | Tie |
Detailed analysis
Intelligence
Winner: Grok 4.20Grok 4.20 scores 49.3 on the intelligence index compared with 38.6 for GPT-5.1-Codex-Mini. This gap favors Grok for tasks requiring deeper reasoning across large multimodal inputs.
Speed
Winner: GPT-5.1-Codex-MiniGPT-5.1-Codex-Mini delivers 214.62 tokens per second versus 168.03 for Grok 4.20. The speed advantage makes it preferable when rapid iteration on code is needed.
Context & Modalities
Winner: Grok 4.20Grok 4.20 supports up to 2M tokens and adds file inputs alongside text and images. GPT-5.1-Codex-Mini is limited to 400k tokens and image+text only, though it emphasizes coding use cases.
Pricing
Winner: GPT-5.1-Codex-MiniGPT-5.1-Codex-Mini costs $2 per million output tokens while Grok 4.20 costs $2.5. The 20% price reduction favors GPT-5.1-Codex-Mini for high-volume usage.
GPT-5.1-Codex-Mini
Pros
- +Very large context window
- +Strong coding specialization
- +Native image + text support
- +Suitable for extended technical workflows
Cons
- –Mini variant may have reduced depth on complex reasoning
- –Limited to image and text modalities
- –Trade-off between context size and response speed
Grok 4.20
Pros
- +Handles extremely large contexts up to 2M tokens
- +Native support for text, image, and file inputs
- +Multimodal integration in a single model
Cons
- –No audio or video modality support
- –Very large context can increase latency
- –Performance depends on input quality and structure
Summary: GPT-5.1-Codex-Mini vs Grok 4.20
Select GPT-5.1-Codex-Mini when coding speed, lower cost, and image-text workflows are priorities. Choose Grok 4.20 when maximum context size and higher intelligence on large multimodal inputs are required. Both remain proprietary models with no public parameter counts disclosed.
Frequently asked questions
Grok 4.20 scores higher on intelligence and offers far larger context, while GPT-5.1-Codex-Mini is faster and cheaper with coding specialization; neither dominates every dimension.