GPT-5.5 vs Llama 3 8B Instruct
GPT-5.5 (2026) and Llama 3 8B 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 8B Instruct ships a 8k-token context window. On MMLU PRO, GPT-5.5 leads by 47.6 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 131x more tokens; pick it for long-context work and Llama 3 8B Instruct for tighter calls.
Decision scorecard
Local evidence first| Signal | GPT-5.5 | Llama 3 8B Instruct |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | Coding, RAG, and Agents | Coding, Classification, and JSON / Tool use |
| Context window | 1.05m | 8k |
| Cheapest output | $30/1M tokens | $0.05/1M tokens |
| Provider routes | 4 tracked | 17 tracked |
| Shared benchmarks | MMLU PRO leader | 5 shared |
Decision tradeoffs
- GPT-5.5 holds a shared-benchmark lead on MMLU PRO, ahead by 47.6 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 8B Instruct has the lower cheapest tracked output price at $0.05/1M tokens.
- Llama 3 8B Instruct has broader tracked provider coverage for fallback and route flexibility.
- Local decision data tags Llama 3 8B Instruct for Coding, Classification, and JSON / Tool use.
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 8B Instruct
$28.50
Cheapest tracked route/tier: DeepInfra
Estimated monthly gap: $11,472. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on AWS Bedrock and OpenRouter; start route-level A/B tests there.
- Llama 3 8B Instruct is $29.95/1M 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 and AWS Bedrock; start route-level A/B tests there.
- GPT-5.5 is $29.95/1M 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 | 2024-04-18 |
| Context window | 1.05m | 8k |
| Parameters | — | 8B |
| 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 | 2023-03 |
Pricing and availability
| Pricing attribute | GPT-5.5 | Llama 3 8B Instruct |
|---|---|---|
| Input price |
| $0.02/1M tokens |
| Output price |
| $0.05/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.5 | Llama 3 8B 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 8B Instruct |
|---|---|---|
| MMLU PRO | 88.1 | 40.5 |
| Google-Proof Q&A | 93.6 | 44.8 |
| HumanEval | 94.2 | 68.2 |
| Instruction-Following Evaluation | 92.1 | 59.5 |
| Massive Multitask Language Understanding | 92.4 | 76.9 |
Continue comparing
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Last reviewed: 2026-07-11. Data sourced from public model cards and provider documentation.