Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
Grok 4.1 Fast
72
Winner · 4/8 categoriesQwen3.5-27B
71
3/8 categoriesGrok 4.1 Fast· Qwen3.5-27B
Pick Grok 4.1 Fast if you want the stronger benchmark profile. Qwen3.5-27B only becomes the better choice if coding is the priority or you want the stronger reasoning-first profile.
Grok 4.1 Fast finishes one point ahead overall, 72 to 71. That is enough to call, but not enough to treat as a blowout. This matchup comes down to a few meaningful edges rather than one model dominating the board.
Grok 4.1 Fast's sharpest advantage is in reasoning, where it averages 87.9 against 60.6. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 74% to 41.6%. Qwen3.5-27B does hit back in coding, so the answer changes if that is the part of the workload you care about most.
Qwen3.5-27B is the reasoning model in the pair, while Grok 4.1 Fast is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Grok 4.1 Fast gives you the larger context window at 1M, compared with 262K for Qwen3.5-27B.
BenchLM keeps the benchmark table and the operator tradeoffs on the same page so a better score does not hide a materially slower, pricier, or smaller-context model.
Runtime metrics show N/A when BenchLM does not have a sourced snapshot for that exact model. The scoring rules and freshness policy are documented on the methodology page.
| Benchmark | Grok 4.1 Fast | Qwen3.5-27B |
|---|---|---|
| AgenticGrok 4.1 Fast wins | ||
| Terminal-Bench 2.0 | 74% | 41.6% |
| BrowseComp | 73% | 61% |
| OSWorld-Verified | 66% | 56.2% |
| tau2-bench | — | 79% |
| CodingQwen3.5-27B wins | ||
| HumanEval | 86% | — |
| SWE-bench Verified | 68% | 72.4% |
| LiveCodeBench | 54% | 80.7% |
| SWE-bench Pro | 63% | — |
| Multimodal & GroundedGrok 4.1 Fast wins | ||
| MMMU-Pro | 91% | 75% |
| OfficeQA Pro | 83% | — |
| ReasoningGrok 4.1 Fast wins | ||
| MuSR | 88% | — |
| BBH | 87% | — |
| LongBench v2 | 87% | 60.6% |
| MRCRv2 | 89% | — |
| KnowledgeQwen3.5-27B wins | ||
| MMLU | 94% | — |
| GPQA | 92% | 85.5% |
| SuperGPQA | 90% | 65.6% |
| MMLU-Pro | 81% | 86.1% |
| HLE | 20% | — |
| FrontierScience | 83% | — |
| SimpleQA | 90% | — |
| Instruction FollowingQwen3.5-27B wins | ||
| IFEval | 90% | 95% |
| MultilingualGrok 4.1 Fast wins | ||
| MGSM | 88% | — |
| MMLU-ProX | 83% | 82.2% |
| Mathematics | ||
| AIME 2023 | 96% | — |
| AIME 2024 | 98% | — |
| AIME 2025 | 97% | — |
| HMMT Feb 2023 | 92% | — |
| HMMT Feb 2024 | 94% | — |
| HMMT Feb 2025 | 93% | — |
| BRUMO 2025 | 95% | — |
| MATH-500 | 89% | — |
Grok 4.1 Fast is ahead overall, 72 to 71. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 74% and 41.6%.
Qwen3.5-27B has the edge for knowledge tasks in this comparison, averaging 80.6 versus 70.9. Inside this category, SuperGPQA is the benchmark that creates the most daylight between them.
Qwen3.5-27B has the edge for coding in this comparison, averaging 77.6 versus 60.7. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for reasoning in this comparison, averaging 87.9 versus 60.6. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for agentic tasks in this comparison, averaging 71 versus 51.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for multimodal and grounded tasks in this comparison, averaging 87.4 versus 75. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
Qwen3.5-27B has the edge for instruction following in this comparison, averaging 95 versus 90. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for multilingual tasks in this comparison, averaging 84.8 versus 82.2. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.
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