Model comparison
Kimi K3 vs Mellum2-12B-A2.5B-Thinking
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: Kimi K3 #4 (Supported); Mellum2-12B-A2.5B-Thinking unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Kimi K3 and Mellum2-12B-A2.5B-Thinking share 2 comparable benchmark results. 1 of 8 categories are comparable. 55 results are unique to Kimi K3; 3 to Mellum2-12B-A2.5B-Thinking.
Updated July 23, 2026- Shared results
- 2
- Kimi K3 only
- 55
- Mellum2-12B-A2.5B-Thinking only
- 3
- Comparable categories
- 1 / 8
Treat this as a split decision. Kimi K3 makes more sense if knowledge is the priority or you need the larger 1.05M context window; Mellum2-12B-A2.5B-Thinking is the better fit if its strengths line up with your actual workload.
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
Kimi K3 and Mellum2-12B-A2.5B-Thinking 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.
Kimi K3 gives you the larger context window at 1.05M, compared with 128K for Mellum2-12B-A2.5B-Thinking.
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 | Kimi K3 | Δ | Mellum2-12B-A2.5B-Thinking |
|---|---|---|---|
| Knowledge | Kimi K361.0 | Margin← 3.4 | Mellum2-12B-A2.5B-Thinking57.6 |
| Agentic | Kimi K389.5 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
| Multimodal | Kimi K378.5 | MarginNo overlap | Mellum2-12B-A2.5B-ThinkingNot measured |
| Inst. Following | Kimi K3Not measured | MarginNo overlap | Mellum2-12B-A2.5B-Thinking76.5 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
GPQA
KnowledgeA 93.5%B 57.6%Winner: Kimi K3Δ 35.9GPQA: Kimi K3 scored 93.5%; Mellum2-12B-A2.5B-Thinking scored 57.6%. Kimi K3 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Kimi K3 | Mellum2-12B-A2.5B-Thinking | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Kimi K3$3 input / $15 output | Mellum2-12B-A2.5B-ThinkingNot available | A complete price comparison is not available. |
| Generation speedtokens per second | Kimi K3Not available | Mellum2-12B-A2.5B-ThinkingNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Kimi K3Not available | Mellum2-12B-A2.5B-ThinkingNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Kimi K31.05M | Mellum2-12B-A2.5B-Thinking128K | Kimi K3 lists the larger context window. |
Benchmark Deep Dive
Agentic22 benchmarks
| Benchmark | Kimi K3 | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 88.3% | — | Not comparable |
| BrowseCompSource | 91.2% | — | Not comparable |
| DeepSearchQASource | 95.0% | — | Not comparable |
| Toolathlon-VerifiedSource | 73.2% | — | Not comparable |
| MCP AtlasSource | 84.2% | — | Not comparable |
| AutomationBenchSource | 30.8% | — | Not comparable |
| JobBenchSource | 52.9% | — | Not comparable |
| APEX-AgentsSource | 37.6% | — | Not comparable |
| SpreadsheetBench 2Source | 34.8% | — | Not comparable |
| DECK-BenchSource | 73.5% | — | Not comparable |
| AA Agentic IndexSource | 50.1% | — | Not comparable |
| GDPval-AASource | 59.0% | — | Not comparable |
| GDPval-AASource | 1679 | — | Not comparable |
| AA BriefcaseSource | 1543 | — | Not comparable |
| AA AutomationBenchSource | 52.7% | — | Not comparable |
| AA EnterpriseOps-GymSource | 45.3% | — | Not comparable |
| AA Harvey LABSource | 94.6% | — | Not comparable |
| AA Tau3 BankingSource | 33.4% | — | Not comparable |
| aaTerminalBench21Source | 85% | — | Not comparable |
| APEX-Agents-AASource | 41.3% | — | Not comparable |
| AA ITBenchSource | 47.7% | — | Not comparable |
| BFCL v4Source | — | 45.6% | Not comparable |
Coding9 benchmarks
| Benchmark | Kimi K3 | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| deepSweSource | 67.5% | — | Not comparable |
| FrontierSWESource | 81.2% | — | Not comparable |
| ProgramBenchSource | 77.8% | — | Not comparable |
| Kimi Code Bench v2Source | 72.9% | — | Not comparable |
| sweMarathonSource | 42% | — | Not comparable |
| PostTrain BenchSource | 36.6% | — | Not comparable |
| MLS-Bench LiteSource | 48.3% | — | Not comparable |
| AA Coding IndexSource | 76.2% | — | Not comparable |
| AA-SciCodeSource | 58.7% | — | Not comparable |
Reasoning2 benchmarks
KnowledgeKimi K3 wins11 benchmarks
| Benchmark | Kimi K3 | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| GPQASource | 93.5% | 57.6% | Kimi K3 leads |
| GPQA-DSource | 93.5% | 57.6% | Kimi K3 leads |
| HLESource | 56% | — | Not comparable |
| HLE w/o toolsSource | 43.5% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 57.1% | — | Not comparable |
| AA-GPQA DiamondSource | 93.5% | — | Not comparable |
| AA-HLESource | 44.3% | — | Not comparable |
| AA-Omniscience IndexSource | 18.4% | — | Not comparable |
| AA-Omniscience AccuracySource | 46.0% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 50.9% | — | Not comparable |
| MMLU-ReduxSource | — | 86.2% | Not comparable |
Multimodal15 benchmarks
| Benchmark | Kimi K3 | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| OfficeQA ProSource | 63.3% | — | Not comparable |
| MMMU-ProSource | 81.6% | — | Not comparable |
| MMMU-Pro w/ PythonSource | 83.4% | — | Not comparable |
| CharXiv w/o toolsSource | 84.8% | — | Not comparable |
| CharXivSource | 91.3% | — | Not comparable |
| MathVisionSource | 94.3% | — | Not comparable |
| MathVision w/ PythonSource | 97.8% | — | Not comparable |
| BabyVision w/ PythonSource | 85.7% | — | Not comparable |
| ZeroBenchSource | 23.0% | — | Not comparable |
| ZeroBench w/ PythonSource | 41.0% | — | Not comparable |
| WorldVQA ForceAnswerSource | 51.0% | — | Not comparable |
| OmniDocBenchSource | 91.1% | — | Not comparable |
| PerceptionBenchSource | 58.5% | — | Not comparable |
| AA-MMMU-ProSource | 80.5% | — | Not comparable |
| Design Arena WebsiteSource | 1386 | — | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Kimi K3 | Mellum2-12B-A2.5B-Thinking | Result |
|---|---|---|---|
| IFEvalSource | — | 76.5% | Not comparable |
Frequently Asked Questions (2)
Which is better, Kimi K3 or Mellum2-12B-A2.5B-Thinking?
Kimi K3 and Mellum2-12B-A2.5B-Thinking 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, Kimi K3 or Mellum2-12B-A2.5B-Thinking?
Kimi K3 has the edge for knowledge tasks in this comparison, averaging 61 versus 57.6. Inside this category, GPQA is the benchmark that creates the most daylight between them.
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