Noometry

Model comparison

DeepSeek V4.1 Flash vs Step 3.5 Flash

DeepSeek V4.1 Flash is the stronger model overall, scoring 52.8 to 42.3 on the Noometry Index. Step 3.5 Flash costs 1.7× less per token, which makes it the better buy when DeepSeek V4.1 Flash's lead doesn't matter for your workload.

Last verified . 18 shared benchmarks.

DeepSeek V4.1 Flash DeepSeek

52.8

Rank #38 Confirmed

Step 3.5 Flash StepFun

42.3

Rank #116 Confirmed

Summary

  • They share 18 benchmarks with published results for both. DeepSeek V4.1 Flash scores higher in 8 categories and Step 3.5 Flash in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where DeepSeek V4.1 Flash leads 50.2 to 22.2.
  • The biggest single-benchmark swing is NYT Connections (extended): 89.6% for DeepSeek V4.1 Flash and 28.4% for Step 3.5 Flash.
  • Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.15 / $0.60 for DeepSeek V4.1 Flash.
  • DeepSeek V4.1 Flash accepts more context: 1M tokens versus 256K.

Side by side

DeepSeek V4.1 FlashStep 3.5 Flash
ProviderDeepSeekStepFun
Noometry Index52.842.3
Released2026-09-092026-01-29
WeightsOpenOpen
Context window1M256K
Max output393K256K
Input $ / M tokens$0.15$0.10
Output $ / M tokens$0.60$0.30
Results tracked3719

Sponsored placements are available on pages like this one. Advertise on Noometry

Category by category

Coding DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 52.9 (#32), Step 3.5 Flash: 42.4 (#105)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Coding15061436
LMArena WebDev1619—
SciCode51.9%—
ALE-Bench1,092—

Agentic & Tool Use Not comparable

DeepSeek V4.1 Flash: 31.2 (#69), Step 3.5 Flash: —

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
APEX-Agents39.5%—
GDP.pdf19.8%—

Reasoning DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 50.2 (#36), Step 3.5 Flash: 22.2 (#202)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
NYT Connections (extended)89.6%28.4%
LMArena Hard Prompts14831411
CritPt14.3%—
Mystery Game Puzzles43%—
DTBench89.9%—
LMCA47%—
Surface Evolver Bench46.3%—
Epoch Capabilities Index154.9—

Math DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 66.7 (#25), Step 3.5 Flash: 42.6 (#84)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Math14771408
FrontierMath (Tiers 1-3)67.4%—
FrontierMath Tier 426.8%—
MathArena Final-Answer Competitions—66.8%
OTIS Mock AIME 2024-202598.3%—
ProofBench54%—

Knowledge DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 57.9 (#38), Step 3.5 Flash: 39.6 (#132)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Expert15061421
GPQA Diamond89.8%—

Multimodal Not comparable

DeepSeek V4.1 Flash: 39.1 (#61), Step 3.5 Flash: —

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Vision1277—
Furniture Assembly34.2%—

Multilingual DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 55.0 (#35), Step 3.5 Flash: 50.5 (#119)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Non-English14481385
LMArena Chinese14971447
LMArena French14521421
LMArena German14841405
LMArena Japanese14121354
LMArena Korean14521352
LMArena Russian14711385
LMArena Spanish14591419

Instruction Following DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 77.3 (#26), Step 3.5 Flash: 73.1 (#124)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Instruction Following14741385

Long Context DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 45.2 (#47), Step 3.5 Flash: 42.8 (#117)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Longer Query14751402

Writing & Preference DeepSeek V4.1 Flash leads

DeepSeek V4.1 Flash: 65.4 (#48), Step 3.5 Flash: 58.8 (#113)

BenchmarkDeepSeek V4.1 FlashStep 3.5 Flash
LMArena Text14621403
LMArena Creative Writing14351357
LMArena Multi-Turn14571405
EQ-Bench Creative Writing1540—

Frequently asked questions

Is DeepSeek V4.1 Flash better than Step 3.5 Flash?

DeepSeek V4.1 Flash is the stronger model overall, scoring 52.8 to 42.3 on the Noometry Index. Step 3.5 Flash costs 1.7× less per token, which makes it the better buy when DeepSeek V4.1 Flash's lead doesn't matter for your workload.

Which is cheaper, DeepSeek V4.1 Flash or Step 3.5 Flash?

Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; DeepSeek V4.1 Flash lists at $0.15 and $0.60.

Is DeepSeek V4.1 Flash or Step 3.5 Flash better for coding?

DeepSeek V4.1 Flash scores higher on coding benchmarks: 52.9 versus 42.4 in the Noometry coding category.

Which has the bigger context window?

DeepSeek V4.1 Flash does, with 1M tokens against 256K.

How many benchmarks do DeepSeek V4.1 Flash and Step 3.5 Flash share?

18 benchmarks have published results for both models. DeepSeek V4.1 Flash has 37 scored results on Noometry and Step 3.5 Flash has 19.

Related comparisons

Go deeper