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Qwen3.5 397B A17B vs Qwen3.5-Flash

Updated October 21, 2026. 39 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Qwen3.5 397B A17B Replace Qwen3.5-Flash
Qwen3.5 397B A17BQwen
Coding
28.6
Overall
21.4
Output $/M
$2.34
38
Qwen3.5-FlashQwen
Coding
6.2
Overall
No data
Output $/M
$0.26
1
vs boards won of 39 shared

Decision reading

Pick Qwen3.5 397B A17B for coding: it scores 28.6 on the Vibe Coding Index against 6.2 for Qwen3.5-Flash.

Pick Qwen3.5-Flash when output tokens cost 9.0x less, or when the context window is larger, 1M against 262K tokens.

Model AQwen3.5 397B A17BQwen28.6/1001 independent benchmarkNo cost per solved taskModel BQwen3.5-FlashQwen6.2/1001 independent benchmark$0.40 per solved task
Shared results
39
Qwen3.5 397B A17B only
26
Qwen3.5-Flash only
16
Like-for-like categories
6 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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
Qwen3.5 397B A17B 28.6 from 1 benchmark, Qwen3.5-Flash 6.2 from 1 benchmark.
Widest category
Coding, 16.2 points apart on average over 6 shared benchmarks.
Widest single gap
LMArena WebDev: React: Qwen3.5 397B A17B 1388 against Qwen3.5-Flash 1229, 26.4 points apart on a 0 to 100 scale.
Output price
Qwen3.5 397B A17B $2.34 against Qwen3.5-Flash $0.26 per million output tokens, 9.0x apart.
Context window
Qwen3.5 397B A17B takes 262K tokens, Qwen3.5-Flash 1M.

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
CategoryQwen3.5 397B A17BBarsQwen3.5-FlashTies
Coding60
Intelligence10
Reasoning41
Math40
Knowledge40
General190
All shared boards381
CodingLike-for-likeFour of these boards feed the Vibe Coding Index60
Coding benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
LMArena WebDev14001244Qwen3.5 397B A17B
LiveCodeBench (Vals AI)Not measured83.3%Only Qwen3.5-Flash measured
SWE-bench Verified (Vals AI)Not measured64.4%Only Qwen3.5-Flash measured
SciCode44.8%Not measuredOnly Qwen3.5 397B A17B measured
Terminal-Bench Hard (Artificial Analysis run)40.9%Not measuredOnly Qwen3.5 397B A17B measured
ALE-Bench621.9265.9Qwen3.5 397B A17B
LMArena Text: coding14641412Qwen3.5 397B A17B
LMArena Text: software and IT14631416Qwen3.5 397B A17B
LMArena WebDev: React13881229Qwen3.5 397B A17B
LMArena WebDev: HTML14101291Qwen3.5 397B A17B
Neither model has a result on the other 28 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
Intelligence benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
AA Intelligence Index21.4Not measuredOnly Qwen3.5 397B A17B measured
Epoch Capabilities Index146.8143.5Qwen3.5 397B A17B
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
Agentic work benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
τ²-Bench Telecom95.6%Not measuredOnly Qwen3.5 397B A17B measured
APEX-Agents24.9%Not measuredOnly Qwen3.5 397B A17B measured
Neither model has a result on the other 37 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index41
Reasoning benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
GPQA DiamondNot measured82.8%Only Qwen3.5-Flash measured
MMMU Pro (Vals AI)Not measured81.9%Only Qwen3.5-Flash measured
GPQA Diamond (Artificial Analysis run)89.3%Not measuredOnly Qwen3.5 397B A17B measured
Humanity's Last Exam (Artificial Analysis run)29.0%Not measuredOnly Qwen3.5 397B A17B measured
GPQA Diamond (Epoch AI run)86.4%82.3%Qwen3.5 397B A17B
Chess puzzlesNot measured14.0%Only Qwen3.5-Flash measured
Mystery game puzzles18.0%20.0%Qwen3.5-Flash
LMArena Text: hard prompts14481403Qwen3.5 397B A17B
LMArena Text: expert14621407Qwen3.5 397B A17B
LMArena Text: hard prompts in English14501409Qwen3.5 397B A17B
LMArena Vision: diagrams1277Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: homework1292Not measuredOnly Qwen3.5 397B A17B measured
Neither model has a result on the other 9 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index40
Math benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
AIMENot measured92.5%Only Qwen3.5-Flash measured
OTIS Mock AIME88.9%84.4%Qwen3.5 397B A17B
FrontierMath, tiers 1 to 331.2%18.2%Qwen3.5 397B A17B
LMArena Text: math14531407Qwen3.5 397B A17B
LMArena Text: mathematical work14541413Qwen3.5 397B A17B
Neither model has a result on the other 8 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
Knowledge benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
MMLU ProNot measured84.1%Only Qwen3.5-Flash measured
LegalBench (Vals AI)Not measured84.3%Only Qwen3.5-Flash measured
CaseLaw (Vals AI)Not measured56.0%Only Qwen3.5-Flash measured
CorpFin (Vals AI)Not measured63.6%Only Qwen3.5-Flash measured
TaxEval (Vals AI)Not measured72.2%Only Qwen3.5-Flash measured
MortgageTax (Vals AI)Not measured67.4%Only Qwen3.5-Flash measured
MedCode (Vals AI)Not measured33.0%Only Qwen3.5-Flash measured
SimpleQA VerifiedNot measured20.3%Only Qwen3.5-Flash measured
LMArena Text: science14571415Qwen3.5 397B A17B
LMArena Text: medicine and healthcare14551407Qwen3.5 397B A17B
LMArena Text: legal and government14411398Qwen3.5 397B A17B
LMArena Text: business and finance14351394Qwen3.5 397B A17B
Neither model has a result on the other 5 boards here
Web designDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared
Web design benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
Design Arena: websites1191Not measuredOnly Qwen3.5 397B A17B measured
Design Arena: UI components1163Not measuredOnly Qwen3.5 397B A17B measured
Design Arena: game dev1141Not measuredOnly Qwen3.5 397B A17B measured
Design Arena: data viz1175Not measuredOnly Qwen3.5 397B A17B measured
Design Arena: 3D1161Not measuredOnly Qwen3.5 397B A17B measured
Design Arena: all code categories1180Not measuredOnly Qwen3.5 397B A17B measured
Design Arena: SVG1139Not measuredOnly Qwen3.5 397B A17B measured
Neither model has a result on the other 2 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index190
General benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-FlashLeader
SAGE (Vals AI)Not measured42.5%Only Qwen3.5-Flash measured
MedScribe (Vals AI)Not measured70.6%Only Qwen3.5-Flash measured
IFBench78.8%Not measuredOnly Qwen3.5 397B A17B measured
Long context reasoning (AA-LCR)77.3%Not measuredOnly Qwen3.5 397B A17B measured
DTBench87.5%82.9%Qwen3.5 397B A17B
LMCA37.9%29.1%Qwen3.5 397B A17B
LMArena Text14371397Qwen3.5 397B A17B
LMArena Text: instruction following14241374Qwen3.5 397B A17B
LMArena Text: creative writing14021343Qwen3.5 397B A17B
LMArena Vision1262Not measuredOnly Qwen3.5 397B A17B measured
LMArena Text: English14431404Qwen3.5 397B A17B
LMArena Text: non-English14301385Qwen3.5 397B A17B
LMArena Text: Chinese14981445Qwen3.5 397B A17B
LMArena Text: German14451390Qwen3.5 397B A17B
LMArena Text: Japanese14291369Qwen3.5 397B A17B
LMArena Text: Korean13841344Qwen3.5 397B A17B
LMArena Text: French14621413Qwen3.5 397B A17B
LMArena Text: Spanish14411400Qwen3.5 397B A17B
LMArena Text: Russian14301380Qwen3.5 397B A17B
LMArena Text: Polish14471376Qwen3.5 397B A17B
LMArena Text: multi-turn14461393Qwen3.5 397B A17B
LMArena Text: longer queries14411392Qwen3.5 397B A17B
LMArena Text: writing and language14151369Qwen3.5 397B A17B
LMArena Text: entertainment and media13991347Qwen3.5 397B A17B
LMArena Vision: English1268Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: Chinese1314Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: reading text1271Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: humor1262Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: captioning1230Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: recognizing things1265Not measuredOnly Qwen3.5 397B A17B measured
LMArena Vision: creative writing1260Not measuredOnly Qwen3.5 397B A17B measured
Neither model has a result on the other 15 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Qwen3.5 397B A17B and Qwen3.5-Flash
BenchmarkQwen3.5 397B A17BQwen3.5-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

Qwen3.5 397B A17B$0.0016Fits in one request
Qwen3.5-Flash$0.0002Fits in one request

Qwen3.5-Flash costs less

Repository review

50K input + 3K output tokens

Qwen3.5 397B A17B$0.027Fits in one request
Qwen3.5-Flash$0.0040Fits in one request

Qwen3.5-Flash costs less

Agent loop

200K input + 10K output tokens

Qwen3.5 397B A17B$0.101Fits in one request
Qwen3.5-Flash$0.016Fits in one request

Qwen3.5-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 Qwen3.5 397B A17B and Qwen3.5-Flash
SpecificationQwen3.5 397B A17BQwen3.5-Flash
MakerQwenQwen
WeightsOpen weightsNo public weights listed
ReleasedFebruary 16, 2026February 25, 2026
Context window262K1M
Input $/Mtok$0.39$0.065
Output $/Mtok$2.34$0.26
Coding index28.66.2
Independent measurements behind it11
Cost per solved taskNot computable$0.40
SourceOpenRouter listingOpenRouter listing

Questions

Is Qwen3.5 397B A17B better than Qwen3.5-Flash for coding?

Pick Qwen3.5 397B A17B for coding: it scores 28.6 on the Vibe Coding Index against 6.2 for Qwen3.5-Flash. Pick Qwen3.5-Flash when output tokens cost 9.0x less, or when the context window is larger, 1M against 262K tokens.

Which is cheaper, Qwen3.5 397B A17B or Qwen3.5-Flash?

Qwen3.5 397B A17B costs $0.39 per million input tokens and $2.34 per million output tokens; Qwen3.5-Flash costs $0.065 and $0.26. Cost per solved task is known for Qwen3.5-Flash only.

Which has the bigger context window, Qwen3.5 397B A17B or Qwen3.5-Flash?

Qwen3.5-Flash, with 1M tokens against 262K.

How many benchmarks is the Qwen3.5 397B A17B vs Qwen3.5-Flash comparison based on?

39 benchmarks have a result for both models as of October 21, 2026. Qwen3.5 397B A17B's coding index rests on 1 independent benchmark and Qwen3.5-Flash's on 1. Where only one model has a result, the page says so instead of naming a winner.

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