DeepSeek V3 vs GPT-5.6
Pricing, benchmarks, and use case comparison
Quick take
- •DeepSeek V3 is meaningfully stronger at cost efficiency (92 vs 70 on our capability index).
- •GPT-5.6 is meaningfully stronger at multimodal (87 vs 10).
- •DeepSeek V3 is open-weights (free to self-host); GPT-5.6 is paid API only.
Specs comparison
| DeepSeek V3 | GPT-5.6 | |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Type | Open source | Closed source |
| Context window | ✓128K tokens | Not announced |
| Input / 1M tokens | ✓Free (self-host) | 5 |
| Output / 1M tokens | Free (self-host) | 30 |
| Release date | 2024-12 | 2026-06 |
Benchmarks
| Benchmark | DeepSeek V3 | GPT-5.6 |
|---|---|---|
| Pre-training scale | ~15T tokens | - |
| Terminal-Bench 2.1 (Sol) | - | 88.8% |
| Terminal-Bench 2.1 (Terra) | - | 82.5% |
| Terminal-Bench 2.1 (Luna) | - | 84.3% |
| Terminal-Bench 2.1 | - | 88.8 |
| ExploitBench | - | Competitive with Anthropic Mythos Preview |
| ExploitGym | - | Significant improvements |
| GeneBench v1 | - | Not announced |
Scores sourced from official provider release posts and independent benchmark aggregators.
Which should you choose?
Choose DeepSeek V3 if...
- →You want a proven, stable open model with broad ecosystem support
- →You need to self-host or fine-tune without licensing friction
- →Cost is critical and you don't need V4's 1M context or top scores
- →You want reproducible open-weight behavior pinned to a known version
Choose GPT-5.6 if...
- →You want to standardize on one model generation but route requests across cost/quality tiers
- →You are an approved preview partner exploring the newest OpenAI capabilities
- →Workloads spanning agentic coding, knowledge work, and research where tier flexibility helps