Model comparison
Gemini 3.5 Flash vs Gemini 3 Pro Deep Think
Head-to-head evidence from 2 shared benchmark results across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Gemini 3.5 Flash #33 (Estimated); Gemini 3 Pro Deep Think #41 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemini 3.5 Flash and Gemini 3 Pro Deep Think share 2 comparable benchmark results. 1 of 8 categories are comparable. 44 results are unique to Gemini 3.5 Flash; 0 to Gemini 3 Pro Deep Think.
Updated July 23, 2026- Shared results
- 2
- Gemini 3.5 Flash only
- 44
- Gemini 3 Pro Deep Think only
- 0
- Comparable categories
- 1 / 8
Pick Gemini 3.5 Flash if you want the stronger benchmark profile. Gemini 3 Pro Deep Think only becomes the better choice if you need the larger 2M context window.
Confidence note. This is a partial-evidence comparison with 2 shared benchmark results across 1 evidence category; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Gemini 3.5 Flash is clearly ahead on the BenchAlign aggregate, 64.75 to 61.31. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Gemini 3.5 Flash's sharpest advantage is in reasoning, where it averages 74.7 against 45.1. The single biggest benchmark swing on the page is ARC-AGI-2, 72.1% to 45.1%.
Gemini 3 Pro Deep Think gives you the larger context window at 2M, compared with 1M for Gemini 3.5 Flash.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Gemini 3.5 Flash | Δ | Gemini 3 Pro Deep Think |
|---|---|---|---|
| Reasoning | Gemini 3.5 Flash74.7 | Margin← 29.6 | Gemini 3 Pro Deep Think45.1 |
| Agentic | Gemini 3.5 Flash77.2 | MarginNo overlap | Gemini 3 Pro Deep ThinkNot measured |
| Coding | Gemini 3.5 Flash53.9 | MarginNo overlap | Gemini 3 Pro Deep ThinkNot measured |
| Knowledge | Gemini 3.5 Flash47.2 | MarginNo overlap | Gemini 3 Pro Deep ThinkNot measured |
| Math | Gemini 3.5 Flash32.9 | MarginNo overlap | Gemini 3 Pro Deep ThinkNot measured |
| Multimodal | Gemini 3.5 Flash83.8 | MarginNo overlap | Gemini 3 Pro Deep ThinkNot measured |
| Inst. Following | Gemini 3.5 Flash76.3 | MarginNo overlap | Gemini 3 Pro Deep ThinkNot measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
ARC-AGI-2
ReasoningA 72.1%B 45.1%Winner: Gemini 3.5 FlashΔ 27ARC-AGI-2: Gemini 3.5 Flash scored 72.1%; Gemini 3 Pro Deep Think scored 45.1%. Gemini 3.5 Flash wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemini 3.5 Flash | Gemini 3 Pro Deep Think | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemini 3.5 Flash$1.5 input / $9 output | Gemini 3 Pro Deep ThinkNot available | A complete price comparison is not available. |
| Generation speedtokens per second | Gemini 3.5 Flash284.2 tok/s | Gemini 3 Pro Deep ThinkNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Gemini 3.5 Flash18.55 s | Gemini 3 Pro Deep ThinkNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Gemini 3.5 Flash1M | Gemini 3 Pro Deep Think2M | Gemini 3 Pro Deep Think lists the larger context window. |
Benchmark Deep Dive
Agentic15 benchmarks
| Benchmark | Gemini 3.5 Flash | Gemini 3 Pro Deep Think | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 76.2% | — | Not comparable |
| MCP AtlasSource | 83.6% | — | Not comparable |
| ToolathlonSource | 56.5% | — | Not comparable |
| OSWorld-VerifiedSource | 78.4% | — | Not comparable |
| Finance Agent v2Source | 57.9% | — | Not comparable |
| GDPval-AASource | 1349 | — | Not comparable |
| τ²-bench resultsSource | 95.3% | — | Not comparable |
| GDPval-AASource | 42.4% | — | Not comparable |
| AA Agentic IndexSource | 37.5% | — | Not comparable |
| APEX-Agents-AASource | 47.1% | — | Not comparable |
| Gert LabsSource | 61.85% | — | Not comparable |
| ResearchClawBenchSource | 18.0% | — | Not comparable |
| AA AutomationBenchSource | 42.6% | — | Not comparable |
| AA EnterpriseOps-GymSource | 50.1% | — | Not comparable |
| terminalBenchHardSource | 40.9% | — | Not comparable |
Coding8 benchmarks
| Benchmark | Gemini 3.5 Flash | Gemini 3 Pro Deep Think | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 76.2% | — | Not comparable |
| SWE-bench ProSource | 55.1% | — | Not comparable |
| SciCodeSource | 53.1% | — | Not comparable |
| Vibe Code BenchSource | 48.68% | — | Not comparable |
| cursorBench31Source | 49.8% | — | Not comparable |
| cursorBench32Source | 48.8% | — | Not comparable |
| AA Coding IndexSource | 70.1% | — | Not comparable |
| AA-SciCodeSource | 53.1% | — | Not comparable |
ReasoningGemini 3.5 Flash wins5 benchmarks
Knowledge9 benchmarks
| Benchmark | Gemini 3.5 Flash | Gemini 3 Pro Deep Think | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 50.2% | — | Not comparable |
| GPQASource | 92.2% | — | Not comparable |
| GPQA-DSource | 92.7% | — | Not comparable |
| HLESource | 40.2% | — | Not comparable |
| AA-Omniscience AccuracySource | 51.9% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 60.7% | — | Not comparable |
| AA-GPQA DiamondSource | 92.2% | — | Not comparable |
| AA-HLESource | 41.0% | — | Not comparable |
| AA-Omniscience IndexSource | 22.7% | — | Not comparable |
Math2 benchmarks
Multimodal5 benchmarks
Frequently Asked Questions (2)
Which is better, Gemini 3.5 Flash or Gemini 3 Pro Deep Think?
Gemini 3.5 Flash is ahead on BenchLM's BenchAlign leaderboard, 64.75 to 61.31. The biggest single separator in this matchup is ARC-AGI-2, where the scores are 72.1% and 45.1%.
Which is better for reasoning, Gemini 3.5 Flash or Gemini 3 Pro Deep Think?
Gemini 3.5 Flash has the edge for reasoning in this comparison, averaging 74.7 versus 45.1. Inside this category, ARC-AGI-2 is the benchmark that creates the most daylight between them.
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