Model comparison

Devstral Small 2505 vs GPT-5.6 Sol

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 34.3 on the Noometry Index. Devstral Small 2505 costs 53× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Last verified . 3 shared benchmarks.

Devstral Small 2505 Mistral AI

34.3

Rank #233 Reported

GPT-5.6 Sol OpenAI

65.0

Rank #7 Confirmed

Summary

  • They share 3 benchmarks with published results for both. Devstral Small 2505 scores higher in 0 categories and GPT-5.6 Sol in 2 categories; 2 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where GPT-5.6 Sol leads 74.8 to 19.7.
  • The biggest single-benchmark swing is CritPt: 0% for Devstral Small 2505 and 32.3% for GPT-5.6 Sol.
  • Devstral Small 2505 is cheaper at $0.10 / $0.30 per million input/output tokens, against $4 / $20 for GPT-5.6 Sol.
  • GPT-5.6 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-5.6 Sol specifications
Devstral Small 2505GPT-5.6 Sol
ProviderMistral AIOpenAI
Noometry Index34.365.0
Released2025-05-072026-07-09
WeightsOpenProprietary
Context window128K1.05M
Max output128K128K
Input $ / M tokens$0.10$4
Output $ / M tokens$0.30$20
Results tracked465

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Category by category

Coding GPT-5.6 Sol leads

Devstral Small 2505: 38.9 (#166), GPT-5.6 Sol: 65.1 (#7)

Coding benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
SciCode28.8%57.1%
DeepSWE—72.7%
FrontierCode—47.5%
SWE-bench Verified (bash only)56.4%—
CursorBench—41.7%
LMArena WebDev—1618
FrontierSWE—32.2%
GSO—76.5%
WeirdML—89.4%
LMArena Coding—1498
MirrorCode—20%
ALE-Bench—2,177

Agentic & Tool Use Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 50.3 (#7)

Agentic & Tool Use benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
APEX-Agents—51.4%
OSWorld 2.0—27.3%
τ²-bench Banking—46.9%
PostTrainBench—36.2%
BALROG—60%
GBAEval—52.6%
GDP.pdf—30.7%
LMArena Search—1257
Vending-Bench 2—9,619

Reasoning GPT-5.6 Sol leads

Devstral Small 2505: 19.7 (#252), GPT-5.6 Sol: 74.8 (#8)

Reasoning benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
Kagi LLM Benchmark37.7%67%
CritPt0%32.3%
ARC-AGI-2—92.5%
SimpleBench—71.7%
NYT Connections (extended)—93.8%
ARC-AGI-1—97.5%
Chess Puzzles—64%
EnigmaEval—37.1%
EBR-Bench—44.8%
LMArena Hard Prompts—1484
Mystery Game Puzzles—58%
DTBench—96%
LMCA—59.2%
Surface Evolver Bench—93.1%
Bench to the Future 3—0.14
Epoch Capabilities Index—161.66

Math Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 85.6 (#9)

Math benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
FrontierMath (Tiers 1-3)—89.1%
FrontierMath Tier 4—82.9%
OTIS Mock AIME 2024-2025—100%
ProofBench—83%
LMArena Math—1474
FrontierMath Erdős—0%

Knowledge Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 64.3 (#18)

Knowledge benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
GPQA Diamond—93.5%
SimpleQA Verified—69.7%
Vectara Hallucination Rate—12.4%
LMArena Expert—1516

Multimodal Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 48.6 (#9)

Multimodal benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
LMArena Vision—1281
Blueprint-Bench 2—33.6%
Furniture Assembly—56.7%
LMArena Document—1483

Multilingual Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 55.3 (#32)

Multilingual benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
LMArena Non-English—1452
LMArena Chinese—1527
LMArena French—1477
LMArena German—1476
LMArena Japanese—1471
LMArena Korean—1442
LMArena Russian—1468
LMArena Spanish—1441

Instruction Following Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 77.7 (#16)

Instruction Following benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
LMArena Instruction Following—1482

Long Context Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 45.4 (#42)

Long Context benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
LMArena Longer Query—1480

Writing & Preference Not comparable

Devstral Small 2505: —, GPT-5.6 Sol: 73.3 (#12)

Writing & Preference benchmarks
BenchmarkDevstral Small 2505GPT-5.6 Sol
LMArena Text—1457
LMArena Creative Writing—1448
EQ-Bench Creative Writing—1972
EQ-Bench 4—1250
LMArena Multi-Turn—1460

Frequently asked questions

Is Devstral Small 2505 better than GPT-5.6 Sol?

GPT-5.6 Sol is the stronger model overall, scoring 65.0 to 34.3 on the Noometry Index. Devstral Small 2505 costs 53× less per token, which makes it the better buy when GPT-5.6 Sol's lead doesn't matter for your workload.

Which is cheaper, Devstral Small 2505 or GPT-5.6 Sol?

Devstral Small 2505 is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; GPT-5.6 Sol lists at $4 and $20.

Is Devstral Small 2505 or GPT-5.6 Sol better for coding?

GPT-5.6 Sol scores higher on coding benchmarks: 65.1 versus 38.9 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Sol does, with 1.05M tokens against 128K.

How many benchmarks do Devstral Small 2505 and GPT-5.6 Sol share?

3 benchmarks have published results for both models. Devstral Small 2505 has 4 scored results on Noometry and GPT-5.6 Sol has 65.

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