DeepSeek V4.1 Flash vs GPT-5.3 Codex
DeepSeek V4.1 Flash 
GPT-5.3 Codex Verdict
- GPT-5.3 Codex (xhigh) leads on quality: 65.4 vs 61.9.
- DeepSeek V4.1 Flash (max) is stronger in coding, composite, long context.
- GPT-5.3 Codex (xhigh) is stronger in agents & tools, knowledge, multimodal, reasoning, instruction following.
- DeepSeek V4.1 Flash (max) is 18× cheaper ($0.262 vs $4.81 per 1M blended).
- DeepSeek V4.1 Flash (max) streams 1.7× faster (215 vs 125 tokens per second).
| Metric | DeepSeek V4.1 Flash (max) | GPT-5.3 Codex (xhigh) |
|---|---|---|
| BenchLeader Index | 61.9 | 65.4 |
| Agents & tools score | 59.6 | 79.8 |
| Coding score | 68.9 | 61.7 |
| Composite score | 74.5 | 70.2 |
| Knowledge score | 61.7 | 69.4 |
| Long context score | 68.5 | 68.2 |
| Multimodal score | 61.4 | 63.0 |
| Reasoning score | 69.5 | 74.4 |
| Instruction following score | – | 73.4 |
| Blended price $/M | $0.262 | $4.81 |
| Output speed | 215 tok/s | 125 tok/s |
| Time to first answer | 10.5 s | 50.8 s |
| Context window | 1M | 400k |
| WeirdML | – | 77.9% |
| LMArena WebDev | 1614 | – |
| LMArena Agent | 4.9 | – |
| LiveBench | 81.1% | – |
| LiveBench Reasoning | 86.7% | – |
| LiveBench Coding | 80.0% | – |
| LiveBench Agentic Coding | 77.3% | – |
| LiveBench Mathematics | 93.3% | – |
| LiveBench Data Analysis | 79.3% | – |
| LiveBench Language | 81.2% | – |
| LiveBench Instruction Following | 70.0% | – |
| AA Intelligence Index | 39.5 | 32.5 |
| IFBench | – | 75.4% |
| AA-LCR | 84.0% | 83.3% |
| MMMU-Pro | 77.0% | 78.5% |
| AA-Omniscience | -5.3 | 10.9 |
| Terminal-Bench Hard | – | 53.0% |
| GPQA Diamond (AA) | – | 91.5% |
| Humanity's Last Exam (AA) | 39.3% | 42.5% |
| SciCode (AA) | 51.9% | – |
| τ²-Bench Telecom (AA) | – | 86.0% |
| LiveCodeBench | – | 87.3% |
| IOI | – | 53.8% |
| SWE-bench (Vals) | – | 78.0% |
| CritPt | 14.3% | 16.9% |
| GDPval (AA) | 56.6% | – |
| Vibe Code Bench v1.1 | – | 61.8% |
| ALE-Bench | – | 1655.2 |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
DeepSeek V4.1 Flash vs GPT-5.3 Codex: questions
- Is DeepSeek V4.1 Flash better than GPT-5.3 Codex?
- GPT-5.3 Codex (xhigh) leads on quality: 65.4 vs 61.9. The BenchLeader Index combines every independent quality benchmark; GPT-5.3 Codex (xhigh) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Is DeepSeek V4.1 Flash better than GPT-5.3 Codex for coding?
- DeepSeek V4.1 Flash scores higher in coding (69 vs 62 on the category index, where 50 is average).
- Is DeepSeek V4.1 Flash better than GPT-5.3 Codex for agentic tasks?
- GPT-5.3 Codex scores higher in agentic tasks (80 vs 60 on the category index, where 50 is average).
- Which is cheaper, DeepSeek V4.1 Flash or GPT-5.3 Codex?
- DeepSeek V4.1 Flash is cheaper: $0.262 against $4.81 per million tokens, blended at three input tokens per output token.
- Which is faster, DeepSeek V4.1 Flash or GPT-5.3 Codex?
- DeepSeek V4.1 Flash streams faster: 215 against 125 output tokens per second.
- Which has the larger context window?
- DeepSeek V4.1 Flash accepts more context: 1M against 400k tokens.