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R1 0528 vs Step 3.5 Flash

Step 3.5 Flash leads R1 0528 on the Artificial Analysis Intelligence Index, 17.0 to 13.1, and Step 3.5 Flash costs 7.3x less per output token ($0.30 vs $2.18 per million). Updated October 21, 2026; 35 benchmarks have a result for both.

Replace R1 0528 Replace Step 3.5 Flash
R1 0528DeepSeek
Coding
No data
Overall
13.1
Output $/M
$2.18
18
Step 3.5 FlashStepFun
Coding
No data
Overall
17.0
Output $/M
$0.30
17
vs boards won of 35 shared

R1 0528 or Step 3.5 Flash: which to pick

Neither model has a coding score yet, so the two cannot be ranked on coding.

Pick R1 0528 for work measured by Terminal-Bench Hard (Artificial Analysis run) or LMArena Text: coding, where it leads.

Model AR1 0528DeepSeekNot benchmarkedNo coding benchmarkNo cost per solved taskModel BStep 3.5 FlashStepFunNot benchmarkedNo coding benchmarkNo cost per solved task
Shared results
35
R1 0528 only
24
Step 3.5 Flash only
0
Like-for-like categories
7 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
R1 0528 not benchmarked, Step 3.5 Flash not benchmarked.
Widest category
Agentic work, 57.9 points apart on average over 1 shared benchmark.
Widest single gap
τ²-Bench Telecom: R1 0528 36.5% against Step 3.5 Flash 94.4%, 57.9 points apart on a 0 to 100 scale.
Output price
R1 0528 $2.18 against Step 3.5 Flash $0.30 per million output tokens, 7.3x apart.
Context window
R1 0528 takes 164K tokens, Step 3.5 Flash 262K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryR1 0528BarsStep 3.5 FlashTies
Coding12
Intelligence01
Agentic work01
Reasoning23
Math02
Knowledge40
General118
All shared boards1817
CodingLike-for-likeSix of these boards feed the Vibe Coding Index12
Coding benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
Aider polyglot71.4%Not measuredOnly R1 0528 measured
LiveCodeBench (Artificial Analysis run)77.0%Not measuredOnly R1 0528 measured
Terminal-Bench Hard (Artificial Analysis run)15.9%32.6%Step 3.5 Flash
WeirdML41.6%Not measuredOnly R1 0528 measured
ALE-Bench804.1Not measuredOnly R1 0528 measured
LMArena Text: coding14271436Step 3.5 Flash
LMArena Text: software and IT14351434R1 0528
Neither model has a result on the other 31 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
Intelligence benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
AA Intelligence Index13.117.0Step 3.5 Flash
Neither model has a result on the other 1 board here
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
τ²-Bench Telecom36.5%94.4%Step 3.5 Flash
METR time horizons53.8%Not measuredOnly R1 0528 measured
DeepResearch Bench35.1%Not measuredOnly R1 0528 measured
Neither model has a result on the other 36 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index23
Reasoning benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
GPQA Diamond (Artificial Analysis run)81.3%83.1%Step 3.5 Flash
Humanity's Last Exam (Artificial Analysis run)15.8%24.5%Step 3.5 Flash
GPQA Diamond (Epoch AI run)76.3%Not measuredOnly R1 0528 measured
ARC-AGI21.2%Not measuredOnly R1 0528 measured
ARC-AGI-21.1%Not measuredOnly R1 0528 measured
SimpleBench40.8%Not measuredOnly R1 0528 measured
LMArena Text: hard prompts14151411R1 0528
LMArena Text: expert13941421Step 3.5 Flash
LMArena Text: hard prompts in English14221421R1 0528
Neither model has a result on the other 12 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index02
Math benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
AA Math Index76.0Not measuredOnly R1 0528 measured
AIME 2025 (Artificial Analysis run)76.0%Not measuredOnly R1 0528 measured
OTIS Mock AIME66.4%Not measuredOnly R1 0528 measured
MATH level 596.6%Not measuredOnly R1 0528 measured
LMArena Text: math14001408Step 3.5 Flash
LMArena Text: mathematical work14151421Step 3.5 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
Knowledge benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
MMLU Pro (Artificial Analysis run)84.9%Not measuredOnly R1 0528 measured
LMArena Text: science14301415R1 0528
LMArena Text: medicine and healthcare14451408R1 0528
LMArena Text: legal and government14191408R1 0528
LMArena Text: business and finance14021394R1 0528
Neither model has a result on the other 12 boards here
Web designDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
Web design benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
Design Arena: websites1149Not measuredOnly R1 0528 measured
Design Arena: UI components1103Not measuredOnly R1 0528 measured
Design Arena: game dev1097Not measuredOnly R1 0528 measured
Design Arena: data viz1182Not measuredOnly R1 0528 measured
Design Arena: 3D1111Not measuredOnly R1 0528 measured
Design Arena: all code categories1139Not measuredOnly R1 0528 measured
Design Arena: SVG1039Not measuredOnly R1 0528 measured
Neither model has a result on the other 2 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index118
General benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
IFBench39.6%66.5%Step 3.5 Flash
Long context reasoning (AA-LCR)55.7%63.0%Step 3.5 Flash
Fiction.LiveBench75.0%Not measuredOnly R1 0528 measured
Creative writing (Lech Mazur)81.9%Not measuredOnly R1 0528 measured
LMArena Text14281403R1 0528
LMArena Text: instruction following13821385Step 3.5 Flash
LMArena Text: creative writing14051357R1 0528
LMArena Text: English14371417R1 0528
LMArena Text: non-English14121385R1 0528
LMArena Text: Chinese14421446Step 3.5 Flash
LMArena Text: German14041405Step 3.5 Flash
LMArena Text: Japanese13911353R1 0528
LMArena Text: Korean13601351R1 0528
LMArena Text: French14171421Step 3.5 Flash
LMArena Text: Spanish14111419Step 3.5 Flash
LMArena Text: Russian14231385R1 0528
LMArena Text: Polish14281389R1 0528
LMArena Text: multi-turn14051404R1 0528
LMArena Text: longer queries13911402Step 3.5 Flash
LMArena Text: writing and language14021372R1 0528
LMArena Text: entertainment and media14001360R1 0528
Neither model has a result on the other 25 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for R1 0528 and Step 3.5 Flash
BenchmarkR1 0528Step 3.5 FlashLeader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

R1 0528$0.0016Fits in one request
Step 3.5 Flash$0.0003Fits in one request

Step 3.5 Flash costs less

Repository review

50K input + 3K output tokens

R1 0528$0.032Fits in one request
Step 3.5 Flash$0.0059Fits in one request

Step 3.5 Flash costs less

Agent loop

200K input + 10K output tokens

R1 0528$0.122Exceeds the context window
Step 3.5 Flash$0.023Fits in one request

Step 3.5 Flash costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of R1 0528 and Step 3.5 Flash
SpecificationDeepSeek R1 0528StepFun Step 3.5 Flash
MakerDeepSeekStepFun
WeightsOpen weightsOpen weights
ReleasedMay 28, 2025January 29, 2026
Context window164K262K
Input $/Mtok$0.50$0.10
Output $/Mtok$2.18$0.30
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it00
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is R1 0528 better than Step 3.5 Flash for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. Pick R1 0528 for work measured by Terminal-Bench Hard (Artificial Analysis run) or LMArena Text: coding, where it leads.

Which is cheaper, R1 0528 or Step 3.5 Flash?

R1 0528 costs $0.50 per million input tokens and $2.18 per million output tokens; Step 3.5 Flash costs $0.10 and $0.30. Cost per solved task is known for neither of them.

Which has the bigger context window, R1 0528 or Step 3.5 Flash?

Step 3.5 Flash, with 262K tokens against 164K.

How many benchmarks is the R1 0528 vs Step 3.5 Flash comparison based on?

35 benchmarks have a result for both models as of October 21, 2026. R1 0528's coding index rests on 0 independent benchmarks and Step 3.5 Flash's on 0. Where only one model has a result, the page says so instead of naming a winner.

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