GLM-5.3 vs GPT-5.6 Sol vs Muse Spark Open
Too close to call on our weighted score (Muse Spark Open 68, GPT-5.6 Sol 66, GLM-5.3 63). The right pick depends on what you value most.
Z.ai (Zhipu)GLM-5.3
63/100- ECI156.2
- Price$1.40 / $4.40
- Context1M
OpenAIGPT-5.6 Sol
66/100- ECI162.6
- Price$4.00 / $20.00
- Context1.05M
MetaMuse Spark Open
68/100- ECI155.1
- Price$1.25 / $4.25
- Context1.05M
Too close to call
It is close. Our weighted score puts them within 2 points (Muse Spark Open 68/100, GPT-5.6 Sol 66/100, GLM-5.3 63/100), so choose by what matters most for your work: GPT-5.6 Sol for raw capability and Muse Spark Open on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-5.6 SolCapabilities Index (ECI): GPT-5.6 Sol 162.6 · GLM-5.3 156.2 · Muse Spark Open 155.1
- Lowest priceMuse Spark OpenMuse Spark Open $2.00 · GLM-5.3 $2.15 · GPT-5.6 Sol $8.00 per 1M tokens (3:1 blend)
- Longest contextGPT-5.6 Sol and Muse Spark OpenGPT-5.6 Sol 1,050,000 · Muse Spark Open 1,048,576 · GLM-5.3 1,000,000 tokens
- Widest inputsMuse Spark OpenGLM-5.3: Text · GPT-5.6 Sol: Text, Images, PDFs · Muse Spark Open: Text, Images, Audio, Video
- Self-hostingGLM-5.3 and Muse Spark OpenPublishes downloadable weights (Muse Model License)
| Measure | Weight | GLM-5.3 | GPT-5.6 Sol | Muse Spark Open |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 92 | 83 |
| Price | 25% | 33 | 7 | 34 |
| Inputs & features | 15% | 45 | 80 | 80 |
| Context window | 10% | 60 | 61 | 61 |
| Overall | 100% | 63/100 | 66/100 | 68/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GLM-5.3Z.ai (Zhipu) | GPT-5.6 SolOpenAI | Muse Spark OpenMeta |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 156.2 | 162.6 (best) | 155.1 |
| ECI rank | #33 of 165 | #12 of 165 (best) | #39 of 165 |
| GPQA DiamondGraduate-level science questions | 90.9% | 93.5% (best) | 88.6% |
| FrontierMath Tiers 1–3Research-level mathematics | 68.8% | 89.1% (best) | 69.8% |
| OTIS Mock AIME 2024–2025Competition mathematics | 91.1% | 100% (best) | 98.1% |
| SimpleQA VerifiedShort factual questions | 41.0% | 69.7% (best) | 56.6% |
| Price per million tokens | |||
| Input | $1.40 | $4.00 | $1.25 (best) |
| Output | $4.40 | $20.00 | $4.25 (best) |
| Cached input | $0.26 (best) | $0.40 | — |
| Blended (3:1) | $2.15 | $8.00 | $2.00 (best) |
| Long-context rate | Same rate | Over 272K: $8.00 / $30.00 | Same rate |
| Price source | Official Z.AI API | Official OpenAI API | Median of 16 providers |
| Limits | |||
| Context window | 1,000,000 tokens | 1,050,000 tokens (best) | 1,048,576 tokens |
| Max output | 131,072 tokens (best) | 128,000 tokens | 131,072 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | No | Yes | Yes |
| PDFs | No | Yes | No |
| Audio | No | No | Yes |
| Video | No | No | Yes |
| Reasoning | Yeslow · high · max | Yeslow · medium · high · xhigh · max | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | No |
| Availability | |||
| Weights | Open | Proprietary | OpenMuse Model License |
| API model ID | glm-5.3 | gpt-5.6-sol | — |
| API providers | 83 (best) | 49 | 16 |
| Released | Aug 14, 2026 | Jul 9, 2026 | Oct 15, 2026 |
| Knowledge cutoff | — | Feb 16, 2026 | Jan 4, 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GLM-5.3$22.80
- GPT-5.6 Sol$80.00
- Muse Spark Open$21.00
Which should you choose?
Which is better: GLM-5.3, GPT-5.6 Sol or Muse Spark Open?
It is close. Our weighted score puts them within 2 points (Muse Spark Open 68/100, GPT-5.6 Sol 66/100, GLM-5.3 63/100), so choose by what matters most for your work: GPT-5.6 Sol for raw capability and Muse Spark Open on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GLM-5.3, GPT-5.6 Sol or Muse Spark Open?
Muse Spark Open is cheaper at $1.25 input / $4.25 output per million tokens (median across 16 API providers). GLM-5.3 costs $1.40 input / $4.40 output per million tokens (official Z.AI API price); GPT-5.6 Sol costs $4.00 input / $20.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for Muse Spark Open versus $2.15 for GLM-5.3 (1.1× as much) and $8.00 for GPT-5.6 Sol (4× as much).
Which scores higher on benchmarks?
GPT-5.6 Sol scores higher on the Capabilities Index (ECI): GPT-5.6 Sol 162.6 (#12 of 165), GLM-5.3 156.2 (#33 of 165) and Muse Spark Open 155.1 (#39 of 165). Their confidence ranges do not overlap (159.6–166.2 vs 154.3–158.5), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT-5.6 Sol 93.5%, GLM-5.3 90.9%, Muse Spark Open 88.6%; FrontierMath Tiers 1–3 — GPT-5.6 Sol 89.1%, Muse Spark Open 69.8%, GLM-5.3 68.8%; OTIS Mock AIME 2024–2025 — GPT-5.6 Sol 100%, Muse Spark Open 98.1%, GLM-5.3 91.1%; SimpleQA Verified — GPT-5.6 Sol 69.7%, Muse Spark Open 56.6%, GLM-5.3 41.0%.
Which is better for coding?
There are no published SWE-bench Verified results for GLM-5.3, GPT-5.6 Sol and Muse Spark Open yet, so there is no like-for-like coding score. On overall capability, GPT-5.6 Sol leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-5.6 Sol and Muse Spark Open have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for GLM-5.3. Maximum output per response: GLM-5.3 up to 131,072, GPT-5.6 Sol up to 128,000, Muse Spark Open up to 131,072 tokens.
Which can read images, PDFs, audio or video?
GLM-5.3 accepts text; GPT-5.6 Sol accepts text, images and PDFs; Muse Spark Open accepts text, images, audio and video. Muse Spark Open handles the widest range of inputs.
Are any of these open source?
GLM-5.3 and Muse Spark Open publishes its weights (Muse Model License) and can be self-hosted; GPT-5.6 Sol is proprietary.
Which is newer?
Muse Spark Open is the newest, released Oct 15, 2026. GLM-5.3 came out Aug 14, 2026; GPT-5.6 Sol came out Jul 9, 2026. Knowledge cutoff: GPT-5.6 Sol Feb 16, 2026, Muse Spark Open Jan 4, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
