Grok 4 vs Grok 4.1 Fast

Overview from our 12-test suite: Grok 4.1 Fast wins 3 benchmarks (structured output 5 vs 4, creative problem solving 4 vs 3, agentic planning 4 vs 3). Grok 4 wins one (safety calibration 2 vs 1). Eight tests tie. Details and task implications:

• Safety calibration: Grok 4 = 2, Grok 4.1 Fast = 1. In our rankings Grok 4 is ranked 12 of 55 (tied with 19 others) for safety calibration; Grok 4.1 Fast is rank 32 of 55. This matters for systems that must refuse dangerous prompts or have strict guardrails.
• Structured output (JSON/schema): Grok 4.1 Fast = 5 (tied for 1st with 24 others), Grok 4 = 4 (rank 26). For schema-constrained APIs and strict format adherence, 4.1 Fast is clearly stronger.
• Creative problem solving: Grok 4.1 Fast = 4 (rank 9 of 54) vs Grok 4 = 3 (rank 30). This impacts ideation, brainstorming, and non-obvious solution generation.
• Agentic planning: Grok 4.1 Fast = 4 (rank 16) vs Grok 4 = 3 (rank 42). For goal decomposition and recovery, 4.1 Fast performs better in our tests.
• Ties (no clear winner in our suite): strategic analysis (both 5, tied for 1st), constrained rewriting (both 4), tool calling (both 4, rank 18 of 54), faithfulness (both 5, tied for 1st), classification (both 4, tied for 1st), long context (both 5, tied for 1st), persona consistency (both 5, tied for 1st), multilingual (both 5). These ties indicate similar performance on long-context retrieval, faithfulness, and multilingual output in our benchmarks. Practical meaning: choose Grok 4.1 Fast where structured outputs, creative ideas, and agentic workflows matter; choose Grok 4 only when the small safety-calibration advantage justifies the high cost.

Prices (per mTOK in the payload): Grok 4 input $3, output $15; Grok 4.1 Fast input $0.2, output $0.5. Treating mTOK as 1k tokens, cost per 1M tokens = price_per_mtok × 1000. Using a 50/50 input/output split as an example: Grok 4 ≈ $9,000 per 1M tokens (($3,000 input + $15,000 output)/2); Grok 4.1 Fast ≈ $350 per 1M (($200 + $500)/2). At 10M tokens/month multiply by 10 (Grok 4 ≈ $90,000 vs Grok 4.1 Fast ≈ $3,500). At 100M tokens/month multiply again (Grok 4 ≈ $900,000 vs Grok 4.1 Fast ≈ $35,000). The payload also lists a priceRatio of 30, reflecting this gap. Who should care: startups, consumer apps, and high-volume APIs should prefer Grok 4.1 Fast for cost-efficiency; enterprises or low-volume research teams that require slightly better safety calibration may consider Grok 4 despite the large cost delta.

Choose Grok 4.1 Fast if you need a cost-efficient, high-context (2M) model that scores better on structured output (5 vs 4), creative problem solving (4 vs 3), and agentic planning (4 vs 3) — ideal for scaled customer support, research, and production agents. Choose Grok 4 if safety calibration is the single critical criterion (score 2 vs 1, rank 12 vs 32) and you can accept roughly a 30× price premium (input/output $3/$15 vs $0.2/$0.5 per mTOK).