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BenchLM

GPT-OSS 120B vs Qwen3.5 Flash

Updated September 27, 2026. Rank says Qwen3.5 Flash is ahead. Price, access, and your workload can each overturn that. Public scores include evidence status and uncertainty.

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Decision reading

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. Use the documented cost, context, and runtime rows instead. 0 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

Model A
OpenAI logo

OpenAI

37.76/100

Supported · Public rank #121

90% interval 24.0–51.5

Model B
Alibaba logo

Alibaba

45.49/100

Estimated · Public rank #93

90% interval 36.4–54.6

Shared results
0
GPT-OSS 120B only
2
Qwen3.5 Flash only
6
Like-for-like categories
0 / 8
Supported: GPT-OSS 120B · Estimated: Qwen3.5 FlashHow the comparison works

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Long documents

    Prompts that approach the documented context limit

    Qwen3.5 Flash

    Qwen3.5 Flash has the larger documented context window.

    Confidence: documented
Show secondary and unsupported calls
  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    GPT-OSS 120B and Qwen3.5 Flash are scored on Estimated evidence for coding, so the reading is directional rather than like-for-like.

    Confidence: limited
  • Agentic work

    Tool use, computer use, and multi-step task completion

    Not enough matched evidence

    Qwen3.5 Flash is not ranked on the public lane for agentic, so no winner is named for agentic.

    Confidence: limited
  • Chat turn cost

    1K fresh input + 500 output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates
  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Not enough matched evidence

    The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. GPT-OSS 120B does not fit this workload in one request. Qwen3.5 Flash has no published cached-input rate, so cached tokens use its listed input rate. GPT-OSS 120B has no comparable published API token rate.

    Confidence: rate-fallback
  • Repository review cost

    50K fresh input + 3K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

Which one for a specific job

Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.

The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.

26.7GPT-OSS 120B26.5Qwen3.5 Flash

Directional only · BenchAlign v5.7

GPT-OSS 120B scores higher, but at least one score rests on Estimated evidence or a different benchmark set. Directional only, no winner.

Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.

Same basis rules as the category table below

What is actually comparable

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

2 categories rest on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

A shared-evidence shape is not available.

BenchLM does not draw a radar or infer missing axes when the matched evidence is too sparse.

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign v5.7 lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Coding

Directional only
GPT-OSS 120B
26.7
Estimated · #96/135
Qwen3.5 Flash
26.5
Estimated · #97/135
Basis
BenchAlign v5.7 lane · 1 vs 2 public rows
Reading
Directional only

Knowledge

Directional only
GPT-OSS 120B
36.9
Estimated · #100/158
Qwen3.5 Flash
43.0
Estimated · #80/158
Basis
BenchAlign v5.7 lane · 0 vs 2 public rows
Reading
Directional only

Agentic

Not comparable
GPT-OSS 120B
19.7
Estimated · #88/105
Qwen3.5 Flash
Not ranked
Basis
BenchAlign v5.7 lane · 1 vs 0 public rows
Reading
Not comparable

Reasoning

Not comparable
GPT-OSS 120B
57.8
Unranked · 2 rankable rows
Qwen3.5 Flash
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multimodal

Not comparable
GPT-OSS 120B
Not ranked
Qwen3.5 Flash
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Multilingual

Not comparable
GPT-OSS 120B
Not ranked
Qwen3.5 Flash
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
GPT-OSS 120B
82.8
#46/124
Qwen3.5 Flash
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Math

Not comparable
GPT-OSS 120B
Not ranked
Qwen3.5 Flash
28.4
Unranked · 2 rankable rows
Basis
Provisional lane · 0 vs 2 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign v5.7) differ from the provisional-lane categories. Unranked scores sit on the provisional lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Bars run 0–100Methodology

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

GPT-OSS 120B
Self-hosted; infrastructure cost varies
Fits in one request
Qwen3.5 Flash
$0.0003
Fits in one request

GPT-OSS 120B has no comparable published API token rate.

Repository review

50K fresh input + 3K output tokens

GPT-OSS 120B
Self-hosted; infrastructure cost varies
Fits in one request
Qwen3.5 Flash
$0.0062
Fits in one request

GPT-OSS 120B has no comparable published API token rate.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

GPT-OSS 120B
Self-hosted; infrastructure cost varies
Does not fit in one request
Cached-input rate unavailable
Qwen3.5 Flash
$0.026
Fits in one request
Cached input priced at the published list-input rate

GPT-OSS 120B does not fit this workload in one request. Qwen3.5 Flash has no published cached-input rate, so cached tokens use its listed input rate. GPT-OSS 120B has no comparable published API token rate.

Cached input falls back to the list input rate only where a cached rate is unpublished

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Context window

Maximum documented context; output-token limits may be lower.

GPT-OSS 120B

128K

Qwen3.5 Flash

1M

API model ID

GPT-OSS 120B

Not sourced

Qwen3.5 Flash

Not sourced

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

GPT-OSS 120B

No comparable hosted API rate

Qwen3.5 Flash

Not published

Documented inputs

GPT-OSS 120B

Not sourced

Qwen3.5 Flash

Not sourced

Documented outputs

GPT-OSS 120B

Not sourced

Qwen3.5 Flash

Not sourced

Provider availability

GPT-OSS 120B

Not sourced

Qwen3.5 Flash

Not sourced

Reasoning profile

GPT-OSS 120B

Non-Reasoning

Qwen3.5 Flash

Reasoning

Weight access

GPT-OSS 120B

Open Weight

Qwen3.5 Flash

Proprietary

License

GPT-OSS 120B

Open Weight

Qwen3.5 Flash

Proprietary

Release date

GPT-OSS 120B

2025-08-05

Qwen3.5 Flash

2026-03-04

If you already use one of these models

Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
The public evidence has no benchmark result shared by both models, so it does not support a quality verdict.
Workload cost
A complete comparable API-rate estimate is not available for both models.
Context tradeoff
Qwen3.5 Flash has the larger documented window (1M).
Run the same representative tasks against both endpoints before changing production traffic.

Questions

Which is better, GPT-OSS 120B or Qwen3.5 Flash?

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. The page therefore keeps the decision tied to the specific documented workload.

Which is better for coding, GPT-OSS 120B or Qwen3.5 Flash?

GPT-OSS 120B scores higher for coding on the public lane, 26.7 to 26.5. GPT-OSS 120B and Qwen3.5 Flash are scored on Estimated evidence for coding, so the reading is directional rather than like-for-like. BenchLM does not name a winner for coding from a directional reading; read the shared benchmark rows directly and test the models on the same task set.

Which is better for agentic tasks, GPT-OSS 120B or Qwen3.5 Flash?

Qwen3.5 Flash is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.

Which costs less, GPT-OSS 120B or Qwen3.5 Flash?

Both models do not have comparable published API token rates, so this page does not name a universal price winner.

Which has the larger context window, GPT-OSS 120B or Qwen3.5 Flash?

Qwen3.5 Flash has the larger documented context window: 1M, compared with 128K.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence8 rows

Agentic

  • Gert Labs

    GPT-OSS 120B29.61%
    Source
    Qwen3.5 Flash—

    Not directly comparable

Coding

  • React Native Evals

    GPT-OSS 120B71.6%
    Source
    Qwen3.5 Flash—

    Not directly comparable

  • LiveCodeBench (Vals)

    GPT-OSS 120B—
    Qwen3.5 Flash83.3%
    Source

    Not directly comparable

  • SWE-bench (Vals)

    GPT-OSS 120B—
    Qwen3.5 Flash64.4%
    Source

    Not directly comparable

Knowledge

  • GPQA Diamond (Vals)

    GPT-OSS 120B—
    Qwen3.5 Flash82.8%
    Source

    Not directly comparable

  • MMLU-Pro (Vals)

    GPT-OSS 120B—
    Qwen3.5 Flash84.1%
    Source

    Not directly comparable

Math

  • FrontierMath v2 (Tiers 1-3)

    GPT-OSS 120B—
    Qwen3.5 Flash6.207%
    Source

    Not directly comparable

  • FrontierMath v2 (Tier 4)

    GPT-OSS 120B—
    Qwen3.5 Flash0.000%
    Source

    Not directly comparable

8 public results · 0 shared

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Last updated September 27, 2026