DeepSeek V4 Pro (Preview) vs Qwen3.8 Max
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 Pro (Preview)—
Qwen Max18.7
DeepSWE 1.1 DeepSWE 1.1: Agents change repository code to resolve software engineering tasks under the stated DeepSWE edition
DeepSeek V4 Pro (Preview)—
Qwen Max · xhigh57.5
WebDev Arena WebDev Arena: Human pairwise preferences in the stated webdev vote pool
DeepSeek V4 Pro (Preview)—
Qwen Max · max1,672
SciCode SciCode: Writing code for real scientific computing problems (physics, biology, math)
DeepSeek V4 Pro (Preview)—
Qwen Max53.2
| Benchmark | DeepSeek V4 Pro (Preview) | Qwen Max |
|---|---|---|
| Terminal-Bench 4.0 | — | 18.7 |
| DeepSWE 1.1 | — | 57.5 · xhigh |
| WebDev Arena | — | 1,672 · max |
| SciCode | — | 53.2 |
Specs
| Spec | DeepSeek V4 Pro (Preview) | Qwen Max |
|---|---|---|
| Input, per 1M | $1.30 | $2 |
| Output, per 1M | $2.60 | $6 |
| Cost per task? | — | $2.67 |
| Speed, tok/s | — | 38 |
| Context | — | 1M |
| Weights | Not verified | Closed |
| Released | — | Aug 2026 |
| See images | — | ✓ |
| Read PDFs | — | Partial |
| Hear audio | — | — |
| Watch video | — | ✓ |
| Call tools | Partial | ✓ |
| Force a tool call | ✓ | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ? |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
DeepSeek V4 Pro (Preview) → Qwen Max
max_tokens range · QwenCloud›
With thinking enabled, max_tokens outside 1–32768 returns HTTP 400; use max_completion_tokens to budget reasoning plus answer without that cap.
File is not delivered · QwenCloud / Responses›
PDF input through Responses returns HTTP 200 without delivering the file to the model; use Chat Completions or DashScope.
Not simultaneously · QwenCloud›
Setting reasoning_effort and thinking_budget together returns an error; set only one.
tool_choice only supports auto or none · QwenCloud›
With thinking enabled, tool_choice supports only auto or none.
Include the word JSON · QwenCloud›
JSON Object mode requires the word JSON in a system or user message; otherwise the API returns an error.
Agent search_strategy not supported · QwenCloud / Chat Completions›
Chat Completions does not support Qwen3.8 agent search_strategy; use the Responses web_search tool for multi-turn retrieval.
Qwen Max → DeepSeek V4 Pro (Preview)