GPT-5.4 vs Grok Code Fast 1

Across our 12-test internal benchmark suite, GPT-5.4 wins 9 categories, Grok Code Fast 1 wins 1, and they tie on 2.

Where GPT-5.4 leads:

• Structured output: 5 vs 4. GPT-5.4 ties for 1st among 54 models (with 24 others); Grok ranks 26th. For APIs that depend on strict JSON schema compliance, this gap matters.
• Strategic analysis: 5 vs 3. GPT-5.4 ties for 1st among 54 models (with 25 others); Grok ranks 36th with only 8 models sharing that score. A two-point gap here is significant for business intelligence, financial analysis, or nuanced tradeoff reasoning.
• Faithfulness: 5 vs 4. GPT-5.4 ties for 1st among 55 models (with 32 others); Grok ranks 34th. Relevant for RAG pipelines or any task where hallucination risk is costly.
• Safety calibration: 5 vs 2. GPT-5.4 ties for 1st among 55 models (with only 4 others) — a rare, meaningful distinction. Grok ranks 12th. A score of 2 is below the 25th percentile (p25 = 1, but p50 = 2), meaning Grok is median on this dimension. For consumer-facing products or regulated industries, this difference is critical.
• Long context: 5 vs 4. GPT-5.4 ties for 1st among 55 models; Grok ranks 38th. GPT-5.4 also holds a 1,050,000-token context window vs Grok's 256,000 — a structural advantage for document-heavy workflows.
• Multilingual: 5 vs 4. GPT-5.4 ties for 1st among 55 models (with 34 others); Grok ranks 36th. Both above the p75 threshold, but GPT-5.4 edges ahead.
• Persona consistency: 5 vs 4. GPT-5.4 ties for 1st among 53 models (with 36 others); Grok ranks 38th.
• Constrained rewriting: 4 vs 3. GPT-5.4 ranks 6th of 53; Grok ranks 31st.
• Creative problem solving: 4 vs 3. GPT-5.4 ranks 9th of 54; Grok ranks 30th.

Where they tie:

• Tool calling: Both score 4, both rank 18th of 54 (29 models share this score). No meaningful difference for function-calling workflows.
• Agentic planning: Both score 5, tied for 1st among 54 models (with 14 others). Neither has an advantage on goal decomposition or failure recovery.

Where Grok Code Fast 1 wins:

• Classification: 4 vs 3. Grok ties for 1st among 53 models (with 29 others); GPT-5.4 ranks 31st. For routing, intent detection, or labeling pipelines, Grok is the stronger choice.

External benchmarks (Epoch AI): GPT-5.4 scores 76.9% on SWE-bench Verified (rank 2 of 12 models tested — sole holder of that score) and 95.3% on AIME 2025 (rank 3 of 23). No external benchmark scores are available in our data for Grok Code Fast 1. The SWE-bench Verified score places GPT-5.4 above the p75 threshold (75.25%) for that benchmark across models we track, suggesting strong real-world code repair capability by that external measure.

GPT-5.4 costs $2.50/M input tokens and $15.00/M output tokens. Grok Code Fast 1 costs $0.20/M input and $1.50/M output — a 12.5x cheaper input and 10x cheaper output. In practice: at 1M output tokens/month, GPT-5.4 costs $15 vs Grok's $1.50 — a $13.50 gap that's easy to absorb. At 10M output tokens/month, that gap becomes $135. At 100M output tokens/month — realistic for a production coding assistant or high-throughput classification pipeline — you're paying $1,500 for GPT-5.4 vs $150 for Grok Code Fast 1, a $1,350/month difference. Developers running large-scale automated pipelines will feel this gap acutely. GPT-5.4's premium is justified if you need its edge on faithfulness, strategic reasoning, or multilingual quality; it's hard to justify for pure agentic coding loops where Grok ties or wins.

Choose GPT-5.4 if: You need top-tier performance on strategic analysis, faithfulness, safety calibration, or multilingual tasks. You're building RAG pipelines, consumer-facing products, or regulated-industry applications where hallucination or safety risks carry real costs. You need the extended 1M+ token context window for large document workloads. Your output volume is low-to-moderate (under 10M tokens/month) and the quality premium justifies the price. You want strong external benchmark validation — GPT-5.4 ranks 2nd on SWE-bench Verified (76.9%, Epoch AI).

Choose Grok Code Fast 1 if: Your primary use case is classification, routing, or agentic coding pipelines where it matches or beats GPT-5.4 at one-tenth the output cost. You're running high-volume automated workflows (10M+ output tokens/month) and the $1,350+/month savings compound meaningfully. You want visible reasoning traces — Grok Code Fast 1 exposes reasoning tokens in its response, which GPT-5.4 does not list as a quirk. Your tasks don't require long context beyond 256K tokens, multilingual output at max quality, or strict safety calibration.