GPT-5.4 vs Mistral Large 3 675B Instruct
GPT-5.4 (2026) and Mistral Large 3 675B Instruct (2025) are frontier reasoning models from OpenAI and MistralAI. GPT-5.4 ships a 1.05m-token context window, while Mistral Large 3 675B Instruct ships a 128k-token context window. On MMLU PRO, GPT-5.4 leads by 2 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GPT-5.4 fits 8x more tokens; pick it for long-context work and Mistral Large 3 675B Instruct for tighter calls.
Decision scorecard
Local evidence first| Signal | GPT-5.4 | Mistral Large 3 675B Instruct |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps and provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1.05m | 128k |
| Cheapest output | $15/1M tokens | $1.50/1M tokens |
| Provider routes | 3 tracked | 5 tracked |
| Shared benchmarks | MMLU PRO leader | 3 rows |
Decision tradeoffs
- GPT-5.4 holds a shared-benchmark lead on MMLU PRO, ahead by 2 points.
- GPT-5.4 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.4 uniquely exposes Reasoning, Function calling, and Tool use in local model data.
- Local decision data tags GPT-5.4 for Coding, RAG, and Agents.
- Mistral Large 3 675B Instruct has the lower cheapest tracked output price at $1.50/1M tokens.
- Mistral Large 3 675B Instruct has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Mistral Large 3 675B Instruct for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.4
$5,750
Cheapest tracked route/tier: OpenAI API
Mistral Large 3 675B Instruct
$775
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $4,975. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Mistral Large 3 675B Instruct is $13.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning, Function calling, and Tool use before moving production traffic.
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- GPT-5.4 is $13.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.4 adds Reasoning, Function calling, and Tool use in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-05 | 2025-12-01 |
| Context window | 1.05m | 128k |
| Parameters | — | 675B |
| Architecture | decoder only | decoder only |
| License | Proprietary | Mistral License |
| Openness | Proprietary | Open weights |
| Commercial use | Commercial use with conditions | Non-commercial only |
| Knowledge cutoff | 2025-08 | 2024-11 |
Pricing and availability
| Pricing attribute | GPT-5.4 | Mistral Large 3 675B Instruct |
|---|---|---|
| Input price |
| $0.50/1M tokens |
| Output price |
| $1.50/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.4 | Mistral Large 3 675B Instruct |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | GPT-5.4 | Mistral Large 3 675B Instruct |
|---|---|---|
| MMLU PRO | 87.5 | 85.5 |
| Google-Proof Q&A | 92.0 | 43.9 |
| τ-bench | 78.3 | 70.2 |
Deep dive
On shared benchmark coverage, MMLU PRO has GPT-5.4 at 87.5 and Mistral Large 3 675B Instruct at 85.5, with GPT-5.4 ahead by 2 points; Google-Proof Q&A has GPT-5.4 at 92 and Mistral Large 3 675B Instruct at 43.9, with GPT-5.4 ahead by 48.1 points; τ-bench has GPT-5.4 at 78.3 and Mistral Large 3 675B Instruct at 70.2, with GPT-5.4 ahead by 8.1 points. The largest visible gap is 48.1 points on Google-Proof Q&A, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on reasoning mode: GPT-5.4, function calling: GPT-5.4, tool use: GPT-5.4, and code execution: GPT-5.4. Both models share vision, multimodal input, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, GPT-5.4 lists tiered pricing: 0-272,000t is $2.50/1M input and $15/1M output; 272,000t+ is $5/1M input and $22.50/1M output, while Mistral Large 3 675B Instruct lists $0.50/1M input and $1.50/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Mistral Large 3 675B Instruct lower by about $5.45 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 3 providers versus 5, so concentration risk also matters.
Choose GPT-5.4 when coding workflow support and larger context windows are central to the workload. Choose Mistral Large 3 675B Instruct when vision-heavy evaluation, lower input-token cost, and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, GPT-5.4 or Mistral Large 3 675B Instruct?
GPT-5.4 supports 1.05m tokens, while Mistral Large 3 675B Instruct supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, GPT-5.4 or Mistral Large 3 675B Instruct?
GPT-5.4 lists tiered pricing: 0-272,000t is $2.50/1M input and $15/1M output; 272,000t+ is $5/1M input and $22.50/1M output. Mistral Large 3 675B Instruct lists $0.50/1M input and $1.50/1M output tokens on the cheapest tracked provider. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.4 or Mistral Large 3 675B Instruct open source?
GPT-5.4 is listed under Proprietary. Mistral Large 3 675B Instruct is listed under Mistral License. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, GPT-5.4 or Mistral Large 3 675B Instruct?
Both GPT-5.4 and Mistral Large 3 675B Instruct expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, GPT-5.4 or Mistral Large 3 675B Instruct?
Both GPT-5.4 and Mistral Large 3 675B Instruct expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run GPT-5.4 and Mistral Large 3 675B Instruct?
GPT-5.4 is available on OpenAI API, OpenRouter, and Vercel AI Gateway. Mistral Large 3 675B Instruct is available on AWS Bedrock, NVIDIA NIM, Mistral AI Studio, Microsoft Foundry, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.