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Model comparison

Gemini 3.5 Flash vs Mellum2-12B-A2.5B-Instruct

Data verified

Head-to-head evidence from 2 shared benchmark results across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.

64.75/100
No comparison
N/A
2 category wins0 category wins

Public leaderboard positions: Gemini 3.5 Flash #33 (Estimated); Mellum2-12B-A2.5B-Instruct unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Gemini 3.5 Flash and Mellum2-12B-A2.5B-Instruct share 2 comparable benchmark results. 2 of 8 categories are comparable. 44 results are unique to Gemini 3.5 Flash; 3 to Mellum2-12B-A2.5B-Instruct.

Updated July 23, 2026
Shared results
2
Gemini 3.5 Flash only
44
Mellum2-12B-A2.5B-Instruct only
3
Comparable categories
2 / 8

Treat this as a split decision. Gemini 3.5 Flash makes more sense if knowledge is the priority or you need the larger 1M context window; Mellum2-12B-A2.5B-Instruct is the better fit if you would rather avoid the extra latency and token burn of a reasoning model.

Confidence note. This is a partial-evidence comparison with 2 shared benchmark results across 1 evidence category; 2 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 and Mellum2-12B-A2.5B-Instruct finish on the same BenchAlign overall score, so this is less about a single winner and more about where the edge shows up. The BenchAlign headline says tie; the benchmark table is where the real choice happens.

Gemini 3.5 Flash is the reasoning model in the pair, while Mellum2-12B-A2.5B-Instruct is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Gemini 3.5 Flash gives you the larger context window at 1M, compared with 128K for Mellum2-12B-A2.5B-Instruct.

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 scores and score margins for Gemini 3.5 Flash and Mellum2-12B-A2.5B-Instruct
CategoryGemini 3.5 FlashΔMellum2-12B-A2.5B-Instruct
KnowledgeGemini 3.5 Flash47.2Margin← 6.3Mellum2-12B-A2.5B-Instruct40.9
Inst. FollowingGemini 3.5 Flash76.3Margin← 0.5Mellum2-12B-A2.5B-Instruct75.8
AgenticGemini 3.5 Flash77.2MarginNo overlapMellum2-12B-A2.5B-InstructNot measured
CodingGemini 3.5 Flash53.9MarginNo overlapMellum2-12B-A2.5B-InstructNot measured
ReasoningGemini 3.5 Flash74.7MarginNo overlapMellum2-12B-A2.5B-InstructNot measured
MathGemini 3.5 Flash32.9MarginNo overlapMellum2-12B-A2.5B-InstructNot measured
MultimodalGemini 3.5 Flash83.8MarginNo overlapMellum2-12B-A2.5B-InstructNot measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · Gemini 3.5 FlashB · Mellum2-12B-A2.5B-Instruct

  1. GPQA

    Knowledge
    Source ↗
    A 92.2%B 40.9%
    Winner: Gemini 3.5 FlashΔ 51.3
    GPQA: Gemini 3.5 Flash scored 92.2%; Mellum2-12B-A2.5B-Instruct scored 40.9%. Gemini 3.5 Flash wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricGemini 3.5 FlashMellum2-12B-A2.5B-InstructComparison
Input / output priceUSD per 1M tokensGemini 3.5 Flash$1.5 input / $9 outputMellum2-12B-A2.5B-InstructNot availableA complete price comparison is not available.
Generation speedtokens per secondGemini 3.5 Flash284.2 tok/sMellum2-12B-A2.5B-InstructNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenGemini 3.5 Flash18.55 sMellum2-12B-A2.5B-InstructNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensGemini 3.5 Flash1MMellum2-12B-A2.5B-Instruct128KGemini 3.5 Flash lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
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
BFCL v4Source —44.2%Not comparable
Coding
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
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
Reasoning
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
MRCRv2Source 77.3%—Not comparable
MRCR 1MSource 26.6%—Not comparable
ARC-AGI-2Source 72.1%—Not comparable
AA-LCRSource 69.3%—Not comparable
CritPtSource 13.1%—Not comparable
KnowledgeGemini 3.5 Flash wins
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
Artificial Analysis Intelligence IndexSource 50.2%—Not comparable
GPQASource 92.2%40.9%Gemini 3.5 Flash leads
GPQA-DSource 92.7%40.9%Gemini 3.5 Flash leads
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
MMLU-ReduxSource —78.1%Not comparable
Math
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
FrontierMath v2 (Tiers 1-3)Source 38.966%—Not comparable
FrontierMath v2 (Tier 4)Source 14.583%—Not comparable
Multimodal
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
CharXivSource 84.2%—Not comparable
MMMU-ProSource 83.6%—Not comparable
Blueprint-Bench 2Source 33.6%—Not comparable
AA-MMMU-ProSource 84.3%—Not comparable
Design Arena WebsiteSource 1285—Not comparable
Inst. FollowingGemini 3.5 Flash wins
BenchmarkGemini 3.5 FlashMellum2-12B-A2.5B-InstructResult
IFBenchSource 76.3%—Not comparable
AA-IFBenchSource 76.3%—Not comparable
IFEvalSource —75.8%Not comparable
Frequently Asked Questions (3)

Which is better, Gemini 3.5 Flash or Mellum2-12B-A2.5B-Instruct?

Gemini 3.5 Flash and Mellum2-12B-A2.5B-Instruct are tied on the BenchAlign overall score, so the right pick depends on which category matters most for your use case.

Which is better for knowledge tasks, Gemini 3.5 Flash or Mellum2-12B-A2.5B-Instruct?

Gemini 3.5 Flash has the edge for knowledge tasks in this comparison, averaging 47.2 versus 40.9. Inside this category, GPQA-D is the benchmark that creates the most daylight between them.

Which is better for instruction following, Gemini 3.5 Flash or Mellum2-12B-A2.5B-Instruct?

Gemini 3.5 Flash has the edge for instruction following in this comparison, averaging 76.3 versus 75.8. Mellum2-12B-A2.5B-Instruct stays close enough that the answer can still flip depending on your workload.

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