Nemotron 3 Ultra (free) Open vs 
GPT-5.6 Luna Paid
Nemotron 3 Ultra (free) vs GPT-5.6 Luna compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.
Prices & specs refreshed from live data · OpenSourceAI.tech
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
Nemotron 3 Ultra (free) vs GPT-5.6 Luna specs
| Spec | Nemotron 3 Ultra (free) | GPT-5.6 Luna |
|---|---|---|
| Maker | NVIDIA | OpenAI |
| Type | Open-weight | Proprietary |
| Context window | 1M tokens | 1.1M tokens |
| Input price | Free/M · free self-host | $1/M |
| Output price | Free/M · free self-host | $6/M |
| Vision / multimodal | No | Yes |
| Tool / function calling | Yes | Yes |
| Self-hostable | Yes | No (API only) |
| License | NVIDIA Open Model | Proprietary |
Feature comparison
| Capability | Nemotron 3 Ultra (free) | GPT-5.6 Luna |
|---|---|---|
| Open weights (downloadable) | ✓ | ✗ |
| Self-hostable | ✓ | ✗ |
| Runs fully offline | ✓ | ✗ |
| Vision / multimodal | ✗ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✓ | ✓ |
Benchmarks: Nemotron 3 Ultra (free) vs GPT-5.6 Luna
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Nemotron 3 Ultra (free) and GPT-5.6 Luna score
| Criterion | Nemotron 3 Ultra (free) | GPT-5.6 Luna |
|---|---|---|
| Cost-efficiency | 5.0 | 4.0 |
| Context window | 5.0 | 5.0 |
| Openness | 5.0 | 1.5 |
| Self-hosting | 5.0 | 1.0 |
| Multimodality | 3.5 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Nemotron 3 Ultra (free) Open
NVIDIA Nemotron 3 Ultra is an open frontier-reasoning and orchestration model from NVIDIA, with 55B active parameters out of 550B total (MoE). Built on a hybrid Transformer-Mamba mixture-of-experts architecture, it...
GPT-5.6 Luna Paid
GPT-5.6 Luna is a fast, cost-efficient model in OpenAI's GPT-5.6 series. It is suited for high-volume, latency-sensitive tasks such as chat, classification, and lightweight agentic workflows, providing capable reasoning for...
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Is Nemotron 3 Ultra (free) as good as GPT-5.6 Luna?
Nemotron 3 Ultra (free) is open-weight and competitive on many tasks, but GPT-5.6 Luna may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.
Can I run Nemotron 3 Ultra (free) locally?
Yes. Nemotron 3 Ultra (free) has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. GPT-5.6 Luna is API-only and cannot be self-hosted.
Nemotron 3 Ultra (free) vs GPT-5.6 Luna — which should I pick in 2026?
Choose Nemotron 3 Ultra (free) if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose GPT-5.6 Luna if you want frontier capability through a managed API with zero infrastructure to run.
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