Model comparison

Devstral Small 2505 vs GPT-6 Sol

GPT-6 Sol is the stronger model overall, scoring 61.8 to 34.3 on the Noometry Index. Devstral Small 2505 costs 27× less per token, which makes it the better buy when GPT-6 Sol's lead doesn't matter for your workload.

Last verified . 2 shared benchmarks.

Devstral Small 2505 Mistral AI

34.3

Rank #233 Reported

GPT-6 Sol OpenAI

61.8

Rank #12 Confirmed

Summary

  • They share 2 benchmarks with published results for both. Devstral Small 2505 scores higher in 0 categories and GPT-6 Sol in 2 categories; 2 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-6 Sol leads 74.0 to 19.7.
  • The biggest single-benchmark swing is CritPt: 0% for Devstral Small 2505 and 30.9% for GPT-6 Sol.
  • Devstral Small 2505 is cheaper at $0.10 / $0.30 per million input/output tokens, against $2 / $10 for GPT-6 Sol.
  • GPT-6 Sol accepts more context: 1.05M tokens versus 128K.
  • Devstral Small 2505 has downloadable open weights; the other is API-only.

Side by side

Devstral Small 2505 and GPT-6 Sol specifications
Devstral Small 2505GPT-6 Sol
ProviderMistral AIOpenAI
Noometry Index34.361.8
Released2025-05-072026-09-22
WeightsOpenProprietary
Context window128K1.05M
Max output128K128K
Input $ / M tokens$0.10$2
Output $ / M tokens$0.30$10
Results tracked445

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Category by category

Coding GPT-6 Sol leads

Devstral Small 2505: 38.9 (#166), GPT-6 Sol: 60.1 (#11)

Coding benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
SciCode28.8%57.6%
DeepSWE—68.8%
FrontierCode—49.3%
SWE-bench Verified (bash only)56.4%—
LMArena WebDev—1688
LMArena Coding—1447
ALE-Bench—2,462

Agentic & Tool Use Not comparable

Devstral Small 2505: —, GPT-6 Sol: 37.2 (#36)

Agentic & Tool Use benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
APEX-Agents—54.3%
GDP.pdf—26.4%
Vending-Bench 2—14,428

Reasoning GPT-6 Sol leads

Devstral Small 2505: 19.7 (#252), GPT-6 Sol: 74.0 (#9)

Reasoning benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
CritPt0%30.9%
ARC-AGI-2—89.6%
Kagi LLM Benchmark37.7%—
NYT Connections (extended)—90.1%
ARC-AGI-1—95.5%
EBR-Bench—53.3%
LMArena Hard Prompts—1418
Mystery Game Puzzles—56%
DTBench—97.3%
LMCA—59.1%
Epoch Capabilities Index—162.72

Math Not comparable

Devstral Small 2505: —, GPT-6 Sol: 87.2 (#7)

Math benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
FrontierMath (Tiers 1-3)—89.8%
FrontierMath Tier 4—90%
OTIS Mock AIME 2024-2025—100%
ProofBench—83%
LMArena Math—1402

Knowledge Not comparable

Devstral Small 2505: —, GPT-6 Sol: 64.8 (#15)

Knowledge benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
GPQA Diamond—94.3%
SimpleQA Verified—60.7%
Vectara Hallucination Rate—6.5%
LMArena Expert—1439

Multimodal Not comparable

Devstral Small 2505: —, GPT-6 Sol: 47.6 (#10)

Multimodal benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
LMArena Vision—1245
Blueprint-Bench 2—36.9%
Furniture Assembly—58.3%

Multilingual Not comparable

Devstral Small 2505: —, GPT-6 Sol: 50.5 (#118)

Multilingual benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
LMArena Non-English—1385
LMArena Chinese—1405
LMArena French—1410
LMArena German—1390
LMArena Japanese—1385
LMArena Korean—1341
LMArena Russian—1401
LMArena Spanish—1384

Instruction Following Not comparable

Devstral Small 2505: —, GPT-6 Sol: 74.5 (#94)

Instruction Following benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
LMArena Instruction Following—1412

Long Context Not comparable

Devstral Small 2505: —, GPT-6 Sol: 43.1 (#108)

Long Context benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
LMArena Longer Query—1411

Writing & Preference Not comparable

Devstral Small 2505: —, GPT-6 Sol: 71.9 (#18)

Writing & Preference benchmarks
BenchmarkDevstral Small 2505GPT-6 Sol
LMArena Text—1395
LMArena Creative Writing—1378
EQ-Bench Creative Writing—2125
LMArena Multi-Turn—1412

Frequently asked questions

Is Devstral Small 2505 better than GPT-6 Sol?

GPT-6 Sol is the stronger model overall, scoring 61.8 to 34.3 on the Noometry Index. Devstral Small 2505 costs 27× less per token, which makes it the better buy when GPT-6 Sol's lead doesn't matter for your workload.

Which is cheaper, Devstral Small 2505 or GPT-6 Sol?

Devstral Small 2505 is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; GPT-6 Sol lists at $2 and $10.

Is Devstral Small 2505 or GPT-6 Sol better for coding?

GPT-6 Sol scores higher on coding benchmarks: 60.1 versus 38.9 in the Noometry coding category.

Which has the bigger context window?

GPT-6 Sol does, with 1.05M tokens against 128K.

How many benchmarks do Devstral Small 2505 and GPT-6 Sol share?

2 benchmarks have published results for both models. Devstral Small 2505 has 4 scored results on Noometry and GPT-6 Sol has 45.

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