DeepSeek V4.1 Flash vs DeepSeek V4.1 Flash 1017
Different efforts: non-thinking · max · Compare all at high
Terminal-Bench 4.0 Terminal-Bench 4.0 · source setting 2: Agents use a terminal to complete executable coding, system administration and research tasks in the 4.0 suite
DeepSeek V4.1 Flash5.6
DeepSeek V4.1 Flash 101733.8
FrontierCode 1.1 FrontierCode 1.1: Agents implement changes in real repositories, graded against maintainer-defined requirements
DeepSeek V4.1 Flash · max44
DeepSeek V4.1 Flash 101743.7
WebDev Arena WebDev Arena: Human pairwise preferences in the stated webdev vote pool
DeepSeek V4.1 Flash · max1,618
DeepSeek V4.1 Flash 1017 · max1,664
SciCode SciCode: Writing code for real scientific computing problems (physics, biology, math)
DeepSeek V4.1 Flash35.5
DeepSeek V4.1 Flash 101755.9
DeepSWE 1.1 DeepSWE 1.1: Agents change repository code to resolve software engineering tasks under the stated DeepSWE edition
DeepSeek V4.1 Flash—
DeepSeek V4.1 Flash 1017 · max53.3
Terminal-Bench Science 0.1 Terminal-Bench Science 0.1: Agents complete expert-authored research workflows across five scientific domains in a terminal
DeepSeek V4.1 Flash · max9
DeepSeek V4.1 Flash 1017—
| Benchmark | DeepSeek V4.1 Flash | DeepSeek V4.1 Flash 1017 |
|---|---|---|
| Terminal-Bench 4.0 | 5.6 | 33.8 |
| FrontierCode 1.1 | 44 · max | 43.7 |
| WebDev Arena | 1,618 · max | 1,664 · max |
| SciCode | 35.5 | 55.9 |
| DeepSWE 1.1 | — | 53.3 · max |
| Terminal-Bench Science 0.1 | 9 · max | — |
Specs
| Spec | DeepSeek V4.1 Flash | DeepSeek V4.1 Flash 1017 |
|---|---|---|
| Input, per 1M | !$0.30 | $0.30 |
| Output, per 1M | !$1.20 | $1.20 |
| Cost per task? | $0.22 | $0.26 |
| Speed, tok/s | 201 | 167 |
| Context | 1M | 1M |
| Weights | Open | Open |
| Released | Sep 2026 | Oct 2026 |
| Memory (4-bit) | — | 458 GB |
| Licence | — | MIT |
| Commercial use | — | Allowed |
| See images | ? | ✓ |
| Read PDFs | ? | — |
| Hear audio | ? | — |
| Watch video | ? | — |
| Call tools | ✓ | ✓ |
| Force a tool call | ? | ✓ |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ? |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
DeepSeek V4.1 Flash → DeepSeek V4.1 Flash 1017
Pass back reasoning_content · Chat Completions›
With thinking and tools, return all prior reasoning_content even on turns without tool calls or the API returns HTTP 400.
Disable thinking mode first · Chat Completions›
Required and named tool choices return HTTP 400 in thinking mode; disable thinking first.
Parameters have no effect›
In thinking mode, temperature, presence_penalty and frequency_penalty have no effect.
Values below 0.95›
Flash clamps top_p below 0.95 to 0.95 while thinking and ignores it in non-thinking mode, using 1.0.
Stateless API · Responses›
Responses does not support previous_response_id or conversation; preserve conversation history in your client.
DeepSeek V4.1 Flash 1017 → DeepSeek V4.1 Flash