LLM Reference

Gemini 2.5 Flash vs Qwen3.5-397B-A17B

Gemini 2.5 Flash (2025) and Qwen3.5-397B-A17B (2026) are frontier reasoning models from Google DeepMind and Alibaba. Gemini 2.5 Flash ships a 1m-token context window, while Qwen3.5-397B-A17B ships a 262k-token context window. On MMLU PRO, Gemini 2.5 Flash leads by 0.6 pts. On pricing, Gemini 2.5 Flash costs $0.30/1M input tokens versus $0.39/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Qwen3.5-397B-A17B is safer overall; choose Gemini 2.5 Flash when coding workflow support matters.

Decision scorecard

Local evidence first
SignalGemini 2.5 FlashQwen3.5-397B-A17B
Best formultimodal apps, tool-calling agents, and long-context analysisreasoning-heavy apps, multimodal apps, and tool-calling agents
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m262k
Cheapest output$2.50/1M tokens$2.34/1M tokens
Provider routes6 tracked4 tracked
Shared benchmarksMMLU PRO leader5 shared

Decision tradeoffs

Choose Gemini 2.5 Flash when...
  • Gemini 2.5 Flash holds a shared-benchmark lead on MMLU PRO, ahead by 0.6 points.
  • Gemini 2.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Gemini 2.5 Flash has broader tracked provider coverage for fallback and route flexibility.
  • Gemini 2.5 Flash uniquely exposes Code execution in local model data.
  • Local decision data tags Gemini 2.5 Flash for Coding, RAG, and Agents.
Choose Qwen3.5-397B-A17B when...
  • Qwen3.5-397B-A17B holds a shared-benchmark lead on Google-Proof Q&A, ahead by 6.5 points.
  • Qwen3.5-397B-A17B has the lower cheapest tracked output price at $2.34/1M tokens.
  • Qwen3.5-397B-A17B uniquely exposes Reasoning in local model data.
  • Local decision data tags Qwen3.5-397B-A17B for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate Gemini 2.5 Flash

Gemini 2.5 Flash

$865

Cheapest tracked route/tier: Google AI Studio

Qwen3.5-397B-A17B

$897

Cheapest tracked route/tier: OpenRouter

Estimated monthly gap: $32.00. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Gemini 2.5 Flash -> Qwen3.5-397B-A17B
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • Qwen3.5-397B-A17B is $0.16/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Code execution before moving production traffic.
  • Qwen3.5-397B-A17B adds Reasoning in local capability data.
Qwen3.5-397B-A17B -> Gemini 2.5 Flash
  • Provider overlap exists on OpenRouter; start route-level A/B tests there.
  • Gemini 2.5 Flash is $0.16/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Check replacement coverage for Reasoning before moving production traffic.
  • Gemini 2.5 Flash adds Code execution in local capability data.

Specs

Specification
Released2025-06-172026-02-16
Context window1m262k
Parameters—397B
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryApache 2.0OSI-approved
OpennessProprietaryOpen source
WeightsNot releasedAvailable
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-01-

Pricing and availability

Pricing attributeGemini 2.5 FlashQwen3.5-397B-A17B
Input price$0.30/1M tokens$0.39/1M tokens
Output price$2.50/1M tokens$2.34/1M tokens
Providers
Google AI StudioGCP Vertex AIReplicate APIOpenRouterVercel AI GatewayInceptron
OpenRouterTogether AIAlibaba Cloud PAI-EASNovita AI

Capabilities

CapabilityGemini 2.5 FlashQwen3.5-397B-A17B
VisionYesYes
MultimodalYesYes
ReasoningNoYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkGemini 2.5 FlashQwen3.5-397B-A17B
MMLU PRO88.487.8
Google-Proof Q&A82.889.3
LiveCodeBench76.283.6
Massive Multi-discipline Multimodal Understanding79.785.0
BFCL56.272.9

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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.