Devstral 2 2512 vs Grok 4.1 Fast

Summary of our 12-test suite head-to-head (scores on a 1–5 scale in our testing):

• Grok 4.1 Fast wins: strategic_analysis 5 vs 4 (Grok ranks tied for 1st of 54), faithfulness 5 vs 4 (Grok tied for 1st of 55), classification 4 vs 3 (Grok tied for 1st of 53), persona_consistency 5 vs 4 (Grok tied for 1st of 53). These translate to better nuanced tradeoff reasoning, stricter adherence to source material, and more consistent character maintenance in our tasks.
• Devstral 2 2512 wins: constrained_rewriting 5 vs 4 (Devstral tied for 1st of 53). That indicates Devstral is superior at tight compression and exact-length rewrites in our tests.
• Ties (equal scores in our testing): structured_output 5/5 (both tied for 1st), creative_problem_solving 4/4 (both rank 9 of 54), tool_calling 4/4 (both rank 18 of 54), long_context 5/5 (both tied for 1st), safety_calibration 1/1, agentic_planning 4/4, multilingual 5/5. For example, both models scored 5 on long_context in our suite and are tied for 1st among many models — Grok offers a 2,000,000 token window vs Devstral’s 262,144 in the payload, which explains parity at very long contexts in our tests but gives Grok an explicit technical edge for extremely large inputs.
• Rankings context: Grok’s 5 on strategic_analysis places it tied for 1st (top tier) while Devstral’s 5 on constrained_rewriting also ties for 1st. In practice this means Grok is the stronger all-around reasoner/classifier/faithful responder in our evaluations, while Devstral is the specialist when you need exact constrained rewrites.

Raw per-mTok prices from the payload: Devstral 2 2512 charges $0.40 input / $2.00 output; Grok 4.1 Fast charges $0.20 input / $0.50 output. Treat 1,000 mToks = 1,000 units (1M tokens = 1,000 mToks):

• 1M tokens (equal input+output volumes): Devstral = $0.401000 + $2.001000 = $2,400 total. Grok = $0.201000 + $0.501000 = $700 total.
• 10M tokens: Devstral = $24,000; Grok = $7,000.
• 100M tokens: Devstral = $240,000; Grok = $70,000. At these volumes the priceRatio (4×) is material: teams with sustained high throughput or narrow margins should prefer Grok 4.1 Fast. Devstral’s higher cost is plausible to justify for niche workloads that need its specific strengths (see benchmarks), but cost-sensitive production deployments and large-context multimodal pipelines should favor Grok.

Choose Devstral 2 2512 if: you need best-in-class constrained rewriting and structured-output compression at hard character limits (Devstral scores 5/5 and ties for 1st on constrained_rewriting), and you can absorb higher per-token costs. Choose Grok 4.1 Fast if: you want better strategic analysis, classification, and faithfulness in our tests (Grok wins those 4 benchmarks), need multimodal/very-large-context support (2,000,000 token window in the payload), or operate at volumes where Grok’s ~4× lower price materially lowers monthly spend.