Model comparison
Kimi K2.5 (Reasoning) vs Nemotron Ultra 253B
Head-to-head evidence from 11 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Kimi K2.5 (Reasoning) #57 (Estimated); Nemotron Ultra 253B #150 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Kimi K2.5 (Reasoning) and Nemotron Ultra 253B share 11 comparable benchmark results. 0 of 8 categories are comparable. 16 results are unique to Kimi K2.5 (Reasoning); 0 to Nemotron Ultra 253B.
Updated July 20, 2026- Shared results
- 11
- Kimi K2.5 (Reasoning) only
- 16
- Nemotron Ultra 253B only
- 0
- Comparable categories
- 0 / 8
Benchmark data for Kimi K2.5 (Reasoning) and Nemotron Ultra 253B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 11 shared benchmark results across 5 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
Kimi K2.5 (Reasoning) is priced at $0.60 input / $3.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Nemotron Ultra 253B. Kimi K2.5 (Reasoning) has the larger context window at 128K, compared with 32K for Nemotron Ultra 253B.
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 K2.5 (Reasoning) | Δ | Nemotron Ultra 253B |
|---|---|---|---|
| Agentic | Kimi K2.5 (Reasoning)55.0 | MarginNo overlap | Nemotron Ultra 253BNot measured |
| Coding | Kimi K2.5 (Reasoning)76.8 | MarginNo overlap | Nemotron Ultra 253BNot measured |
| Knowledge | Kimi K2.5 (Reasoning)87.2 | MarginNo overlap | Nemotron Ultra 253BNot measured |
| Multimodal | Kimi K2.5 (Reasoning)78.5 | MarginNo overlap | Nemotron Ultra 253BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Kimi K2.5 (Reasoning) | Nemotron Ultra 253B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Kimi K2.5 (Reasoning)$0.6 input / $3 output | Nemotron Ultra 253B$0 input / $0 output | Nemotron Ultra 253B has the lower combined listed price. |
| Generation speedtokens per second | Kimi K2.5 (Reasoning)Not available | Nemotron Ultra 253BNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Kimi K2.5 (Reasoning)Not available | Nemotron Ultra 253BNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Kimi K2.5 (Reasoning)128K | Nemotron Ultra 253B32K | Kimi K2.5 (Reasoning) lists the larger context window. |
Benchmark Deep Dive
Agentic8 benchmarks
| Benchmark | Kimi K2.5 (Reasoning) | Nemotron Ultra 253B | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 50.8% | — | Not comparable |
| BrowseCompSource | 60.6% | — | Not comparable |
| APEX-Agents-AASource | 11.5% | — | Not comparable |
| τ²-bench resultsSource | 95.9% | 11.4% | Kimi K2.5 (Reasoning) leads |
| Gert LabsSource | 32.58% | — | Not comparable |
| AA Agentic IndexSource | 21.7% | — | Not comparable |
| GDPval-AASource | 25.4% | — | Not comparable |
| GDPval-AASource | 1009 | — | Not comparable |
Coding4 benchmarks
Reasoning2 benchmarks
Knowledge8 benchmarks
| Benchmark | Kimi K2.5 (Reasoning) | Nemotron Ultra 253B | Result |
|---|---|---|---|
| GPQASource | 87.6% | — | Not comparable |
| MMLU-ProSource | 87.1% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 35.4% | 9.1% | Kimi K2.5 (Reasoning) leads |
| AA-GPQA DiamondSource | 87.9% | 72.8% | Kimi K2.5 (Reasoning) leads |
| AA-HLESource | 29.4% | 8.1% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience IndexSource | -8.1% | -45.5% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience AccuracySource | 34.3% | 19.9% | Kimi K2.5 (Reasoning) leads |
| AA-Omniscience Hallucination RateSource | 64.6% | 81.7% | Kimi K2.5 (Reasoning) leads |
Math1 benchmarks
| Benchmark | Kimi K2.5 (Reasoning) | Nemotron Ultra 253B | Result |
|---|---|---|---|
| AIME 2025Source | 96.1% | — | Not comparable |
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Kimi K2.5 (Reasoning) | Nemotron Ultra 253B | Result |
|---|---|---|---|
| AA-IFBenchSource | 70.2% | 38.2% | Kimi K2.5 (Reasoning) leads |
Frequently Asked Questions (3)
Can I compare Kimi K2.5 (Reasoning) and Nemotron Ultra 253B on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Kimi K2.5 (Reasoning) and Nemotron Ultra 253B today?
Kimi K2.5 (Reasoning): $0.60 input / $3.00 output per 1M tokens Nemotron Ultra 253B: $0.00 input / $0.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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