In short
How they differ.
Worked out from the figures below. Prices and specs are the makers' own, read Oct 20, 2026.
- GPT-6.1 Sol reads more at once: a context window of 1M tokens against 1M.
- Muse Spark Open can be downloaded and run on your own machine; GPT-6.1 Sol can't.
- On the 1 independent board that rank both, GPT-6.1 Sol places higher on 1 and Muse Spark Open on 0.
Side by side
The specs.
| GPT-6.1 Sol | Muse Spark Open | |
|---|---|---|
| Made by | OpenAI · US | Meta · US |
| Released | Sep 29, 2026 | Oct 15, 2026 |
| Price per 1M tokens | $2 in / $10 out | Free to download; hosts set prices |
| Context window | 1M | 1M |
| Takes in | text, image | text, image, video, audio |
| Download and run it yourself | No | Yes (Muse Model License) |
| Size | Not published | 816B parameters, 42B active |
| Maker says | “Near-Astra performance for complex work at a lower cost.” | “The most capable US open-weight model to date. Build your way, anywhere.” |
| Sources | Prices, Oct 20, 2026 · Description | Prices, Oct 20, 2026 · Description |
Independent tests
Where they place.
Position on each board we follow (1 is best). Epoch AI's and Vectara's scores are shown; the other boards are linked for their own figures.
| Board | GPT-6.1 Sol | Muse Spark Open |
|---|---|---|
| Epoch Capabilities IndexEpoch AI, Oct 20, 2026 | #3166.32 | Not listed |
| LMArena coding chatsLMArena, Oct 15, 2026 | #10 | Not listed |
| LMArena WebDevLMArena, Oct 19, 2026 | #4 | Not listed |
| LMArena visionLMArena, Oct 19, 2026 | #9 | Not listed |
| LMArena Agent ArenaLMArena, Oct 19, 2026 | #4 | Not listed |
| Humanity's Last ExamScale AI | Not listed | #11 |
| SWE-Bench ProScale AI, Sep 22, 2026 | #7 | #11 |
| MultiChallengeScale AI, Feb 3, 2026 | #1 | Not listed |
| Vals IndexVals AI, Oct 19, 2026 | #7 | Not listed |
| Terminal-Bench 4.0Vals AI, Oct 19, 2026 | #7 | Not listed |
| Vibe Code BenchVals AI, Oct 18, 2026 | #8 | Not listed |
| ProofBenchVals AI, Oct 12, 2026 | #5 | Not listed |
More comparisons