Muse Spark Open vs Mistral Large 4
Quick Answer
Muse Spark Open and Mistral Large 4 are the largest recent open-weight-intended models from a US lab and a European lab. On the independent benchmark we track they are essentially tied. The practical difference today is availability: Muse Spark Open’s weights are downloadable now under a license with clear terms, while Mistral Large 4 is still a public preview whose weights and license had not been published as of October 24, 2026. Spark Open also accepts audio and video input. Mistral offers a European-operated deployment option that matters for some data-residency requirements.
At a Glance
| Muse Spark Open | Mistral Large 4 | |
|---|---|---|
| Developer | Meta Superintelligence Labs | Mistral AI |
| Status | Released Oct 15, 2026 | Public preview since Oct 6, 2026 |
| Parameters | 816B total, 42B active | 1.05T total, 52B active |
| Architecture | MoE, 256 experts (8 per token) | Granular MoE, hybrid instruct and reasoning |
| Context | 1M tokens | 1M per Mistral’s docs; ~512K to 524K on some API listings |
| Input | Text, image, video, audio | Text, image |
| Weights | Downloadable (gated form) | Promised by end of October; not yet published |
| License | Muse Model License (attribution, $20M service threshold) | Not yet published |
| AA Intelligence Index (v4.3.2) | 39 | 38 (preview) |
| AA cost per index task | ~$0.84 (provider median) | ~$1.13 |
| API price (per 1M tokens) | Set by providers; median ~$1.25 / $4.25 | $1.36 input / $4.18 output (Mistral) |
Total vs Active Parameters
Both are Mixture-of-Experts models, so their headline sizes describe memory, not compute per token. Spark Open activates about 42B parameters per token; Large 4 about 52B. Active parameters drive speed and serving cost per token. Total parameters, 816B versus about 1.05T, drive how much hardware you need to hold the model. Neither number tells you quality: on the independent index, the smaller model scores marginally higher.
Licensing and Weights
This is where the two differ most today.
Muse Spark Open’s weights are on Hugging Face behind a gated form that asks for your full legal name, date of birth, and organization. The Muse Model License requires a visible “Built with Muse Spark Open” notice and a separate agreement with Meta before offering the model as an API service once revenue tops $20 million a year. Internal use, research, and use inside your own product are excluded from that clause. It is open-weight, not open source.
Mistral describes Large 4 as open-weight, but until the files and license appear you cannot plan around either. Mistral Large 3 was Apache 2.0; reports expect a custom license for Large 4. Mistral also said reinforcement learning was still running at preview launch, so the final model may differ from what you test now.
Capability
Benchmarks the companies publish favor their own models on different tests. Meta reports 60 on DeepSWE 1.1 and strong agent results such as 80.4 on OSWorld Verified. Mistral reports 61.7 on DeepSWE v1.1, strong cybersecurity and legal results, and a second-place finish in a blind human coding evaluation run by Surge AI. The independent index places them within a point. Spark Open’s audio and video input is a real difference if you need multimodal understanding beyond images.
Running Them
Hosted: Spark Open is served by several providers including Baseten, Fireworks AI, Groq, Together AI, and OpenRouter, so prices vary. Large 4 is available through Mistral’s API and Studio, across European, US, and global regions, including a Mistral-operated European deployment under European law.
Self-hosted: Spark Open needs at least 700GB of GPU memory in NVFP4, or two M5 Ultra Mac Studios via MLX. Large 4 will need comparable or larger infrastructure once weights ship. Either is a data-center or serious workstation project, not a laptop model; see When Local AI Makes Sense.
Choose Muse Spark Open If
You want to download and self-host now, you need audio or video input, the Muse Model License terms work for you, or you want provider choice for hosted inference.
Choose Mistral Large 4 If
You need a European supplier or EU-operated deployment, Mistral’s strengths in cybersecurity, legal, and document work match your use case, and you can wait for the final release and license.
When Neither Is Ideal
If you want a permissive license today, DeepSeek V4.1 Flash is MIT-licensed and scores higher on the same index at much lower cost; see Muse Spark Open vs DeepSeek V4.1 Flash. If you need to run locally on one GPU, look at Muse Glimmer or Qwen3.8-27B.
Final Recommendation
Today, Muse Spark Open is the more usable open-weight option because you can actually get it. Revisit Mistral Large 4 once its weights and license are published and independent results on the final model appear.
Related Comparisons
See also Frontier Open Models Explained and Open Models vs Closed Models.
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Frequently Asked Questions
Can I download Mistral Large 4 today?
Not as of October 24, 2026. Mistral Large 4 is in public preview through Mistral's API and Studio, and Mistral has promised the weights by the end of October, with its Hugging Face placeholder pointing to October 31. The license had not been published. Muse Spark Open's weights are already downloadable under the Muse Model License.
Which is better, Muse Spark Open or Mistral Large 4?
On Artificial Analysis's independent Intelligence Index (v4.3.2) they are nearly tied: 39 for Muse Spark Open and 38 for the Mistral Large 4 preview. Each company's own benchmarks favor its model on different tasks. The bigger practical differences are that Spark Open's weights are available now and it accepts audio and video input.
What hardware do I need to self-host Muse Spark Open?
Meta's model card lists at least 700GB of GPU memory for the NVFP4 version and about 2TB for BF16. Meta says it is optimized to run on two Mac Studios with M5 Ultra chips using MLX. Mistral Large 4, at about 1.05 trillion total parameters, will need similar multi-GPU infrastructure once weights ship.
Can I use these models commercially?
Muse Spark Open, yes, under the Muse Model License: you must display 'Built with Muse Spark Open' and sign a separate agreement with Meta if you offer it as an API service with more than $20 million in revenue. Mistral Large 4's license had not been published; Mistral Large 3 used Apache 2.0, but do not assume Large 4 will.
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