Claude Fable 5.1 vs MiMo-V2.6-Pro-UltraSpeed vs GPT-6 Astra
MiMo-V2.6-Pro-UltraSpeed comes out ahead, 44 to 36 and 36 on our weighted score, and it is the cheaper option too.
AnthropicClaude Fable 5.1
36/100- ECI164.8
- Price$10.00 / $50.00
- Context1M
- Our pick
XiaomiMiMo-V2.6-Pro-UltraSpeed
44/100- ECI—
- Price$4.35 / $8.70
- Context1.05M
OpenAIGPT-6 Astra
36/100- ECI166.5
- Price$10.00 / $50.00
- Context1.05M
MiMo-V2.6-Pro-UltraSpeed is our pick
MiMo-V2.6-Pro-UltraSpeed is the better all-round choice, scoring 44/100 against GPT-6 Astra (36) and Claude Fable 5.1 (36). It leads on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceMiMo-V2.6-Pro-UltraSpeedMiMo-V2.6-Pro-UltraSpeed $5.44 · Claude Fable 5.1 $20.00 · GPT-6 Astra $20.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6 Astra and MiMo-V2.6-Pro-UltraSpeedGPT-6 Astra 1,050,000 · MiMo-V2.6-Pro-UltraSpeed 1,048,576 · Claude Fable 5.1 1,000,000 tokens
- Widest inputsMiMo-V2.6-Pro-UltraSpeedClaude Fable 5.1: Text, Images, PDFs · MiMo-V2.6-Pro-UltraSpeed: Text, Images, Audio, Video · GPT-6 Astra: Text, Images, PDFs
- Self-hostingMiMo-V2.6-Pro-UltraSpeedPublishes downloadable weights
| Measure | Weight | Claude Fable 5.1 | MiMo-V2.6-Pro-UltraSpeed | GPT-6 Astra |
|---|---|---|---|---|
| Price | 50% | 0 | 15 | 0 |
| Inputs & features | 30% | 80 | 80 | 80 |
| Context window | 20% | 60 | 61 | 61 |
| Overall | 100% | 36/100 | 44/100 | 36/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Fable 5.1Anthropic | MiMo-V2.6-Pro-UltraSpeedXiaomi | GPT-6 AstraOpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 164.8 | — | 166.5 (best) |
| ECI rank | #4 of 148 | — | #2 of 148 (best) |
| GPQA DiamondGraduate-level science questions | — | — | 95.8% |
| FrontierMath Tiers 1–3Research-level mathematics | 90.2% | — | 93.7% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% | — | 100% |
| SimpleQA VerifiedShort factual questions | 70.8% | — | 75.6% (best) |
| Price per million tokens | |||
| Input | $10.00 | $4.35 (best) | $10.00 |
| Output | $50.00 | $8.70 (best) | $50.00 |
| Cached input | $0.25 | $0.036 (best) | $1.00 |
| Blended (3:1) | $20.00 | $5.44 (best) | $20.00 |
| Long-context rate | Same rate | Same rate | Over 272K: $20.00 / $75.00 |
| Price source | Official Anthropic API | Official Xiaomi API | Official OpenAI API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens | 1,050,000 tokens (best) |
| Max output | 128,000 tokens | 131,072 tokens (best) | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yes | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | claude-fable-5-1 | mimo-v2.6-pro-ultraspeed | gpt-6-astra |
| API providers | 29 (best) | 9 | 26 |
| Released | Sep 1, 2026 | Sep 21, 2026 | Sep 4, 2026 |
| Knowledge cutoff | Jun 2026 | — | Apr 30, 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Claude Fable 5.1$200.00
- MiMo-V2.6-Pro-UltraSpeed$60.90
- GPT-6 Astra$200.00
Which should you choose?
Which is better: Claude Fable 5.1, MiMo-V2.6-Pro-UltraSpeed or GPT-6 Astra?
MiMo-V2.6-Pro-UltraSpeed is the better all-round choice, scoring 44/100 against GPT-6 Astra (36) and Claude Fable 5.1 (36). It leads on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, Claude Fable 5.1, MiMo-V2.6-Pro-UltraSpeed or GPT-6 Astra?
MiMo-V2.6-Pro-UltraSpeed is cheaper at $4.35 input / $8.70 output per million tokens (official Xiaomi API price). Claude Fable 5.1 costs $10.00 input / $50.00 output per million tokens (official Anthropic API price); GPT-6 Astra costs $10.00 input / $50.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $5.44 per million tokens for MiMo-V2.6-Pro-UltraSpeed versus $20.00 for Claude Fable 5.1 (3.7× as much) and $20.00 for GPT-6 Astra (3.7× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. Claude Fable 5.1 has an ECI of 164.8, MiMo-V2.6-Pro-UltraSpeed has not been scored yet and GPT-6 Astra has an ECI of 166.5.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Fable 5.1, MiMo-V2.6-Pro-UltraSpeed and GPT-6 Astra yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-6 Astra and MiMo-V2.6-Pro-UltraSpeed have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for Claude Fable 5.1. Maximum output per response: Claude Fable 5.1 up to 128,000, MiMo-V2.6-Pro-UltraSpeed up to 131,072, GPT-6 Astra up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Fable 5.1 accepts text, images and PDFs; MiMo-V2.6-Pro-UltraSpeed accepts text, images, audio and video; GPT-6 Astra accepts text, images and PDFs. MiMo-V2.6-Pro-UltraSpeed handles the widest range of inputs.
Are any of these open source?
MiMo-V2.6-Pro-UltraSpeed publishes its weights and can be self-hosted; Claude Fable 5.1 and GPT-6 Astra is proprietary.
Which is newer?
MiMo-V2.6-Pro-UltraSpeed is the newest, released Sep 21, 2026. GPT-6 Astra came out Sep 4, 2026; Claude Fable 5.1 came out Sep 1, 2026. Knowledge cutoff: Claude Fable 5.1 Jun 2026, GPT-6 Astra Apr 30, 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 Oct 4, 2026.
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