Grok 4.20 vs Grok Code Fast 1

Across our 12-test suite Grok 4.20 wins 9 categories, Grok Code Fast 1 wins 2, and 1 ties. Details (scores shown are from our tests):

• Structured output: Grok 4.20 5 vs Grok Code Fast 1 4 — Grok 4.20 is tied for 1st of 54 (tied with 24 others), meaning it is more reliable for strict JSON/schema compliance in our testing. This reduces post-processing errors in production pipelines.
• Strategic analysis: 5 vs 3 — Grok 4.20 ranks tied for 1st of 54, so it handles nuanced trade-off reasoning and numeric cost/benefit work better in our benchmarks.
• Constrained rewriting: 4 vs 3 — Grok 4.20 (rank 6 of 53) is stronger for hard character/space-limited rewrites.
• Creative problem solving: 4 vs 3 — Grok 4.20 (rank 9 of 54) produces more feasible, non-obvious ideas in our tests.
• Tool calling: 5 vs 4 — Grok 4.20 tied for 1st of 54, showing superior function selection, argument accuracy and sequencing in our tool-calling scenarios.
• Faithfulness: 5 vs 4 — Grok 4.20 tied for 1st of 55, meaning fewer hallucinations against source material in our tests.
• Long context: 5 vs 4 — Grok 4.20 tied for 1st of 55, so retrieval at 30K+ tokens was more accurate in our evaluation.
• Persona consistency & Multilingual: Grok 4.20 scores 5 vs 4 (both tied for 1st in persona and tied for 1st in multilingual), indicating stronger character maintenance and non-English parity in our runs.
• Classification: tie 4 vs 4 — both models scored equally in routing/categorization tasks (tied for 1st with 29 others for Grok Code Fast 1, Grok 4.20 also tied for 1st with 29 others).
• Safety calibration: Grok 4.20 1 vs Grok Code Fast 1 2 — Grok Code Fast 1 ranks 12 of 55 (better at refusing harmful prompts while permitting legitimate ones in our tests).
• Agentic planning: Grok 4.20 4 vs Grok Code Fast 1 5 — Grok Code Fast 1 is tied for 1st of 54 on agentic planning, so it decomposes goals and recovers from failures better in our scenarios. Interpretation: Grok 4.20 is the stronger generalist for structured, long-context, and tool-heavy tasks; Grok Code Fast 1 is the better, cheaper option when planning, safety calibration, or visible reasoning traces are primary needs.

Costs are materially different. Pricing in the payload is per mtok: Grok 4.20 charges $2 input + $6 output = $8 per mtok; Grok Code Fast 1 charges $0.20 input + $1.50 output = $1.70 per mtok. Interpreting mtok as 1,000 tokens, that yields: for 1M tokens/month Grok 4.20 ≈ $8,000 vs Grok Code Fast 1 ≈ $1,700; for 10M tokens ≈ $80,000 vs $17,000; for 100M tokens ≈ $800,000 vs $170,000. Teams doing high-volume inference (10M+ tokens) will see six-figure differences and should prioritize the cheaper model or architect to reduce output tokens. Small teams or feature-critical services that rely on Grok 4.20’s higher scores may justify the premium; cost-sensitive prototypes and large-scale pipelines should favor Grok Code Fast 1 to control spend.

Choose Grok 4.20 if you need top-tier tool calling, long-context retrieval, strict structured outputs, or the highest faithfulness in production workflows — it won 9 of 12 benchmarks in our testing and ranks tied for 1st in tool calling, faithfulness, long context, and structured output. Choose Grok Code Fast 1 if budget is the priority (≈$1,700 vs $8,000 per 1M tokens) or if agentic planning, safety calibration, and visible reasoning traces are critical — it wins agentic planning and safety calibration and exposes reasoning tokens for steerable developer workflows.