GPT-4o vs Mistral Small 4

Summary (our 12-test suite): Mistral Small 4 wins 5 tests, GPT-4o wins 1, and 6 tests tie. Detailed walk-through (scores are from our testing):

• Structured output: Mistral 5 vs GPT-4o 4 — Mistral ties for 1st on this test (ranked tied 1st of 54), indicating stronger JSON/schema compliance for integrations.
• Creative problem solving: Mistral 4 vs GPT-4o 3 — Mistral ranks 9 of 54 vs GPT-4o rank 30, meaning Small 4 produces more non‑obvious, feasible ideas in our prompts.
• Strategic analysis: Mistral 4 vs GPT-4o 2 — Mistral ranks 27 of 54 vs GPT-4o 44, so Mistral better handles nuanced tradeoff reasoning and numeric judgments in our scenarios.
• Safety calibration: Mistral 2 vs GPT-4o 1 — Mistral ranks 12 of 55 vs GPT-4o 32, showing Mistral is more likely to correctly refuse harmful requests in our tests.
• Multilingual: Mistral 5 vs GPT-4o 4 — Mistral ties for 1st (tied with 34 others), so it delivers higher-quality non‑English outputs in our samples.
• Classification: GPT-4o 4 vs Mistral 2 — GPT-4o ties for 1st in our classification tests (tied for 1st with 29 others), while Mistral ranks 51 of 53; GPT-4o is the clear winner for routing/labeling accuracy in our suite.
• Ties (equal scores in our testing): constrained rewriting 3, tool calling 4, faithfulness 4, long context 4, persona consistency 5, agentic planning 4 — these represent areas where either model performs similarly in our scenarios. External benchmarks (attributed): on SWE-bench Verified (Epoch AI) GPT-4o scores 31%; on MATH Level 5 GPT-4o scores 53.3%; on AIME 2025 GPT-4o scores 6.4% — these external numbers are from Epoch AI and reflect specific coding/math tasks for GPT-4o; Mistral Small 4 has no external scores in the payload. Overall: Mistral Small 4 wins more of our internal tests and is the stronger value; GPT-4o’s notable advantage in classification (and presence of external SWE/MATH/AIME scores in the payload) matters if those tasks are your priority.

Raw per‑million costs from the payload: GPT-4o input $2.50 / 1M tokens and output $10.00 / 1M; Mistral Small 4 input $0.15 / 1M and output $0.60 / 1M. Combined (1M input + 1M output) costs: GPT-4o $12.50 vs Mistral $0.75 (price ratio 16.67). If your workload is evenly split input/output, per total-token-month costs are: 1M tokens → GPT-4o ~$6.25 vs Mistral ~$0.375; 10M → $62.50 vs $3.75; 100M → $625 vs $37.50. If you are output‑heavy (common for content generation), per 1M output tokens: GPT-4o $10 vs Mistral $0.60 (10M → $100 vs $6; 100M → $1,000 vs $60). The cost gap matters for high‑volume APIs, startups, or consumer apps; for low‑volume research or cases where GPT-4o’s single classification win is critical, the premium may be acceptable.

Choose Mistral Small 4 if: you need the best value-per-token and stronger results on structured output, creative problem solving, strategic analysis, safety calibration, or multilingual tasks (it wins 5 of 12 tests and costs $0.75 per 1M in+out). Choose GPT-4o if: classification and routing accuracy is critical (GPT-4o 4 vs Small 4 2 in our tests), or you require GPT-4o’s reported modalities/context features in the payload (text+image+file->text, 128k context, 16,384 max output tokens) and are willing to pay a ~16.7× price premium.