Claude Sonnet 4.5vsGrok 4.1 Fast
Claude Sonnet 4.5 | Grok 4.1 Fast | |
|---|---|---|
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 79%Best | 19% |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 77.2% | — |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 50% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 83.4% | — |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | 68% | — |
| Overview | ||
| Company | Anthropic | SpaceXAI |
| Release date | Sep 29 2025 | Nov 19 2025 |
| Access | Proprietary | Proprietary |
Which is better: Claude Sonnet 4.5 or Grok 4.1 Fast?
Claude Sonnet 4.5 leads Grok 4.1 Fast on 1 of the 1 benchmark they both report (BullshitBench v2). Claude Sonnet 4.5 shipped 51 days before Grok 4.1 Fast, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
On BullshitBench v2, Claude Sonnet 4.5 leads at 79% vs Grok 4.1 Fast at 19%.
Frequently asked questions
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
Grok 4.1 Fast was released by SpaceXAI on Nov 19 2025.
Other comparisons
Claude Sonnet 4.5vsGPT-5.6 SolGrok 4.1 FastvsGPT-5.6 SolClaude Sonnet 4.5vsGemini 3.6 FlashGrok 4.1 FastvsGemini 3.6 FlashClaude Sonnet 4.5vsMuse GlimmerGrok 4.1 FastvsMuse GlimmerClaude Sonnet 4.5vsDeepSeek-V4-Flash-0731Grok 4.1 FastvsDeepSeek-V4-Flash-0731Claude Sonnet 4.5vsMistral Medium 3.5Grok 4.1 FastvsMistral Medium 3.5Claude Sonnet 4.5vsKimi K3Grok 4.1 FastvsKimi K3