GPT-6 Astra (Fast) vs DeepSeek V4 Flash Vision Exp vs Claude Mythos 5
DeepSeek V4 Flash Vision Exp comes out ahead, 65 to 33 and 33 on our weighted score, and it is the cheaper option too.
OpenAIGPT-6 Astra (Fast)
33/100- ECI—
- Price$20.00 / $100.00
- Context1.05M
- Our pick
DeepSeekDeepSeek V4 Flash Vision Exp
65/100- ECI—
- Price$0.216 / $0.647
- Context1M
AnthropicClaude Mythos 5
33/100- ECI—
- Price$10.00 / $50.00
- Context1M
DeepSeek V4 Flash Vision Exp is our pick
DeepSeek V4 Flash Vision Exp is the better all-round choice, scoring 65/100 against GPT-6 Astra (Fast) (33) and Claude Mythos 5 (33). 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 priceDeepSeek V4 Flash Vision ExpDeepSeek V4 Flash Vision Exp $0.323 · Claude Mythos 5 $20.00 · GPT-6 Astra (Fast) $40.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6 Astra (Fast)GPT-6 Astra (Fast) 1,050,000 · DeepSeek V4 Flash Vision Exp 1,000,000 · Claude Mythos 5 1,000,000 tokens
- Widest inputsGPT-6 Astra (Fast) and Claude Mythos 5GPT-6 Astra (Fast): Text, Images, PDFs · DeepSeek V4 Flash Vision Exp: Text, Images · Claude Mythos 5: Text, Images, PDFs
- Self-hostingDeepSeek V4 Flash Vision ExpPublishes downloadable weights (MIT)
| Measure | Weight | GPT-6 Astra (Fast) | DeepSeek V4 Flash Vision Exp | Claude Mythos 5 |
|---|---|---|---|---|
| Price | 50% | 0 | 70 | 0 |
| Inputs & features | 30% | 70 | 60 | 70 |
| Context window | 20% | 61 | 60 | 60 |
| Overall | 100% | 33/100 | 65/100 | 33/100 |
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 | GPT-6 Astra (Fast)OpenAI | DeepSeek V4 Flash Vision ExpDeepSeek | Claude Mythos 5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | — | — | — |
| ECI rank | — | — | — |
| Price per million tokens | |||
| Input | $20.00 | $0.216 (best) | $10.00 |
| Output | $100.00 | $0.647 (best) | $50.00 |
| Cached input | — | — | — |
| Blended (3:1) | $40.00 | $0.323 (best) | $20.00 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Median of 1 providers | Median of 14 providers | Median of 2 providers |
| Limits | |||
| Context window | 1,050,000 tokens (best) | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 384,000 tokens (best) | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yes | Yes | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | No | No | No |
| Availability | |||
| Weights | Proprietary | OpenMIT | Proprietary |
| API model ID | — | — | — |
| API providers | 1 | 15 (best) | 2 |
| Released | Sep 4, 2026 | Aug 21, 2026 | Jun 9, 2026 |
| Knowledge cutoff | — | — | Jan 31, 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-6 Astra (Fast)$400.00
- DeepSeek V4 Flash Vision Exp$3.45
- Claude Mythos 5$200.00
Which should you choose?
Which is better: GPT-6 Astra (Fast), DeepSeek V4 Flash Vision Exp or Claude Mythos 5?
DeepSeek V4 Flash Vision Exp is the better all-round choice, scoring 65/100 against GPT-6 Astra (Fast) (33) and Claude Mythos 5 (33). 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, GPT-6 Astra (Fast), DeepSeek V4 Flash Vision Exp or Claude Mythos 5?
DeepSeek V4 Flash Vision Exp is cheaper at $0.216 input / $0.647 output per million tokens (median across 14 API providers). Claude Mythos 5 costs $10.00 input / $50.00 output per million tokens (median across 2 API providers); GPT-6 Astra (Fast) costs $20.00 input / $100.00 output per million tokens (median across 1 API provider). At a typical mix of three input tokens to one output token, that is $0.323 per million tokens for DeepSeek V4 Flash Vision Exp versus $20.00 for Claude Mythos 5 (62× as much) and $40.00 for GPT-6 Astra (Fast) (124× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers all three models yet. GPT-6 Astra (Fast) has not been scored yet, DeepSeek V4 Flash Vision Exp has not been scored yet and Claude Mythos 5 has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-6 Astra (Fast), DeepSeek V4 Flash Vision Exp and Claude Mythos 5 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 (Fast) has the largest context window at 1,050,000 tokens, against 1,000,000 for DeepSeek V4 Flash Vision Exp and 1,000,000 for Claude Mythos 5. Maximum output per response: GPT-6 Astra (Fast) up to 128,000, DeepSeek V4 Flash Vision Exp up to 384,000, Claude Mythos 5 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GPT-6 Astra (Fast) accepts text, images and PDFs; DeepSeek V4 Flash Vision Exp accepts text and images; Claude Mythos 5 accepts text, images and PDFs. GPT-6 Astra (Fast) handles the widest range of inputs.
Are any of these open source?
DeepSeek V4 Flash Vision Exp publishes its weights (MIT) and can be self-hosted; GPT-6 Astra (Fast) and Claude Mythos 5 is proprietary.
Which is newer?
GPT-6 Astra (Fast) is the newest, released Sep 4, 2026. DeepSeek V4 Flash Vision Exp came out Aug 21, 2026; Claude Mythos 5 came out Jun 9, 2026. Knowledge cutoff: Claude Mythos 5 Jan 31, 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.
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