GPT-5.5 vs Llama 3.1 70B Instruct
GPT-5.5 (2026) and Llama 3.1 70B Instruct (2024) are frontier reasoning models from OpenAI and AI at Meta. GPT-5.5 ships a 1.05m-token context window, while Llama 3.1 70B Instruct ships a 128k-token context window. On HumanEval, GPT-5.5 leads by 10.1 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GPT-5.5 fits 8x more tokens; pick it for long-context work and Llama 3.1 70B Instruct for tighter calls.
Decision scorecard
Local evidence first| Signal | GPT-5.5 | Llama 3.1 70B Instruct |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Long context |
| Context window | 1.05m | 128k |
| Cheapest output | $30/1M tokens | $0.40/1M tokens |
| Provider routes | 4 tracked | 13 tracked |
| Shared benchmarks | HumanEval leader | 2 shared |
Decision tradeoffs
- GPT-5.5 holds a shared-benchmark lead on HumanEval, ahead by 10.1 points.
- GPT-5.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.5 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags GPT-5.5 for Coding, RAG, and Agents.
- Llama 3.1 70B Instruct has the lower cheapest tracked output price at $0.40/1M tokens.
- Llama 3.1 70B Instruct has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Llama 3.1 70B Instruct for Coding, RAG, and Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.5
$11,500
Cheapest tracked route/tier: OpenAI API 0-272K input tokens
Llama 3.1 70B Instruct
$420
Cheapest tracked route/tier: Hyperbolic AI Inference
Estimated monthly gap: $11,080. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter, AWS Bedrock, and Vercel AI Gateway; start route-level A/B tests there.
- Llama 3.1 70B Instruct is $29.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Provider overlap exists on OpenRouter, Vercel AI Gateway, and AWS Bedrock; start route-level A/B tests there.
- GPT-5.5 is $29.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.5 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-23 | 2024-07-23 |
| Context window | 1.05m | 128k |
| Parameters | — | 70B |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Llama 3 Community |
| Openness | Proprietary | Open weights |
| Weights | Not released | Available |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-12 | 2023-12 |
Pricing and availability
| Pricing attribute | GPT-5.5 | Llama 3.1 70B Instruct |
|---|---|---|
| Input price |
| $0.40/1M tokens |
| Output price |
| $0.40/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.5 | Llama 3.1 70B Instruct |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| JSON / 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-5.5 | Llama 3.1 70B Instruct |
|---|---|---|
| HumanEval | 94.2 | 84.1 |
| Massive Multitask Language Understanding | 92.4 | 86.0 |
Continue comparing
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Last reviewed: 2026-07-11. Data sourced from public model cards and provider documentation.