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Head-to-head comparison

gpt-oss-120b vs Qwen3.5 4B

gpt-oss-120b (OpenAI) and Qwen3.5 4B (Qwen) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 19 September 2026

As of 19 September 2026, Qwen3.5 4B holds the stronger ModelCap Index position (#123 vs #124).

Which should you choose?

Choose gpt-oss-120b if…

  • you want provider choice — 20 listed API providers against 0.
  • AA Humanity's Last Exam is your yardstick — 19.6% against 9.9%.

Choose Qwen3.5 4B if…

  • you want the stronger overall ModelCap Index position — #123 against #124 (39.9 vs 38.9 points).
  • AA τ²-Bench Telecom is your yardstick — 92.1% against 65.8%.
  • you want the more recently listed model — Qwen3.5 4B was listed 27 February 2026, gpt-oss-120b 5 August 2025.

gpt-oss-120b vs Qwen3.5 4B: specs, pricing and context

Specification comparison of gpt-oss-120b and Qwen3.5 4B
Fieldgpt-oss-120bOpenAIQwen3.5 4BQwen
ModelCap Index position#124#123
Index score38.939.9
EvidenceMeasuredEstimated
Input price / 1M tokens$0.15Unlisted
Output price / 1M tokens$0.60Unlisted
Context window131K tokens— tokens
Max output tokens66K—
API providers listed200
Weight accessOpen weightsOpen weights
Input modalitiesTextText, Image
First listed5 August 202527 February 2026
PublisherOpenAIQwen

Evidence: 3 public benchmark observations across 3 boards · publisher-corpus-prior over 195 held-out anchors (22%); launch card against 3 resolved peers on 10 rows (79%); exceeds every named peer on 2 of 10 rows; optimism haircut 0.6 from cross-lab-probe; shrunk 3.1 up toward the measured corpus. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: gpt-oss-120b vs Qwen3.5 4B

Public benchmark boards where gpt-oss-120b or Qwen3.5 4B has a published result
Boardgpt-oss-120bQwen3.5 4BLeads
Arena codingArena (LMArena)13911383–1398—Only one result
SWE-benchSWE-bench (Princeton / SWE-agent team)26.0%—Only one result
AA Intelligence IndexArtificial Analysis11.6intelligence-index:v4.3:high—Only one result
AA τ²-Bench TelecomArtificial Analysis65.8%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="gpt-oss-120b (high)":reasoning=true92.1%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="Qwen3.5 4B (Reasoning)":reasoning=trueQwen3.5 4B
AA Humanity's Last ExamArtificial Analysis19.6%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="gpt-oss-120b (high)":reasoning=true9.9%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="Qwen3.5 4B (Reasoning)":reasoning=truegpt-oss-120b

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

gpt-oss-120b vs Qwen3.5 4B: common questions

Is gpt-oss-120b better than Qwen3.5 4B?

Qwen3.5 4B ranks higher on the ModelCap Index as of 19 September 2026: #123 against #124. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is gpt-oss-120b cheaper than Qwen3.5 4B?

At least one of the two has no listed API price on ModelCap right now, so no price comparison is made.

Which has the bigger context window, gpt-oss-120b or Qwen3.5 4B?

Both publish a 131K-token context window.

Which is better for coding, gpt-oss-120b or Qwen3.5 4B?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are gpt-oss-120b and Qwen3.5 4B open-weight models?

gpt-oss-120b: Open weights. Qwen3.5 4B: Open weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run gpt-oss-120b and Qwen3.5 4B?

ModelCap currently lists 20 API providers for gpt-oss-120b and 0 for Qwen3.5 4B, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this gpt-oss-120b vs Qwen3.5 4B comparison?

Every figure comes from the sealed ModelCap dataset published 19 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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