# A.X K2 vs Claude Opus 4.5

> Side-by-side benchmark comparison for A.X K2 and Claude Opus 4.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/a-x-k2-vs-claude-opus-4-5
- Last updated: September 10, 2026

- Shared sourced benchmarks: 4
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Pick Claude Opus 4.5 if you want the stronger benchmark profile. A.X K2 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Claude Opus 4.5 leads overall 58.41 to 49.
- The biggest single benchmark swing is IFBench in Instruction Following, with scores of 75.9% and 58%.
- A.X K2 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- A.X K2 also has the larger context window at 262K.

## Model Snapshot

| Property | A.X K2 | Claude Opus 4.5 |
|----------|----------|----------|
| Creator | SK Telecom | Anthropic |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 262K | 200K |
| Overall Score | null | 58.41 |
| Benchmarks Covered | 10 | 45 |
| Pricing (input/output) | $0.00 / $0.00 | $5.00 / $25.00 |

## Category Breakdown

### Agentic

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 43.2 (Estimated · #97/152)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 36.0% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | Coming soon | 59.3% | Coming soon |
| OSWorld-Verified | Coming soon | 66.3% | Coming soon |
| OSWorld | Coming soon | 66.3% | Coming soon |
| Claw-Eval | Coming soon | 59.6% | Coming soon |
| QwenClawBench | Coming soon | 52.3% | Coming soon |
| τ³-bench results | Coming soon | 70.2% | Coming soon |
| VITA-Bench | Coming soon | 23.3% | Coming soon |
| DeepPlanning | Coming soon | 26.4% | Coming soon |
| Toolathlon | Coming soon | 43.5% | Coming soon |
| MCP Atlas | Coming soon | 42.3% | Coming soon |
| MCP-Tasks | Coming soon | 71.8% | Coming soon |
| WideResearch | Coming soon | 76.4% | Coming soon |
| CyberGym | Coming soon | 50.6% | Coming soon |
| Gert Labs | Coming soon | 64.23% | Coming soon |
| JobBench | Coming soon | 32.3% | Coming soon |

### Coding

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 56.6 (Estimated · #36/151)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 84.0% | 84.8% | Claude Opus 4.5 |
| SciCode | 41% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 36.0% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 80.9% | Coming soon |
| SWE-bench Pro | Coming soon | 57.1% | Coming soon |
| SWE Multilingual | Coming soon | 77.5% | Coming soon |
| NL2Repo | Coming soon | 43.2% | Coming soon |

### Multimodal & Grounded

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 23.5 (#46/48)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | Coming soon | 70.6% | Coming soon |
| MathVision | Coming soon | 74.3% | Coming soon |
| CharXiv | Coming soon | 68.5% | Coming soon |
| VideoMMMU | Coming soon | 84.4% | Coming soon |
| ScreenSpot Pro | Coming soon | 45.7% | Coming soon |
| V* | Coming soon | 67.0% | Coming soon |

### Reasoning

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 72.1 (Unranked · 4 rankable rows)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| LongBench v2 | Coming soon | 64.4% | Coming soon |
| AI-Needle | Coming soon | 74% | Coming soon |

### Knowledge

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 53.9 (Estimated · #61/183)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| HLE | 27.8% | 30.8% | Claude Opus 4.5 |
| GPQA-D | 85.6% | Coming soon | Coming soon |
| GPQA | Coming soon | 87% | Coming soon |
| SuperGPQA | Coming soon | 70.6% | Coming soon |
| MMLU-Pro | Coming soon | 89.5% | Coming soon |
| MMLU-Redux | Coming soon | 96.6% | Coming soon |
| C-Eval | Coming soon | 92.2% | Coming soon |

### Instruction Following

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 39.5 (#105/123)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| IFBench | 75.9% | 58% | A.X K2 |
| IFEval | Coming soon | 90.9% | Coming soon |

### Multilingual

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 82.9 (#2/12)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| MMLU-ProX | Coming soon | 85.7% | Coming soon |
| NOVA-63 | Coming soon | 56.7% | Coming soon |

### Mathematics

- Winner: Coming soon
- A.X K2 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 58.3 (#6/7)

| Benchmark | A.X K2 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | 97.1% | 95.1% | A.X K2 |
| Apex | 45.8% | Coming soon | Coming soon |
| Apex Shortlist | 88.6% | Coming soon | Coming soon |
| HMMT Feb 2025 | Coming soon | 92.9% | Coming soon |
| HMMT Nov 2025 | Coming soon | 93.3% | Coming soon |
| HMMT Feb 2026 | Coming soon | 85.3% | Coming soon |
| MMAnswerBench | Coming soon | 84.0% | Coming soon |
| FrontierMath v2 (Tiers 1-3) | Coming soon | 20.690% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 4.167% | Coming soon |

## FAQ

### Which is better overall, A.X K2 or Claude Opus 4.5?

Claude Opus 4.5 is ahead overall on BenchLM right now.

### How many benchmarks does A.X K2 cover on BenchLM?

A.X K2 currently has 10 sourced benchmark scores on BenchLM.

### How many benchmarks does Claude Opus 4.5 cover on BenchLM?

Claude Opus 4.5 currently has 45 sourced benchmark scores on BenchLM.

## Related Comparisons

- [A.X K2 vs A.X series](/compare/a-x-k2-vs-skt-ax)
- [Claude Opus 4.5 vs A.X series](/compare/claude-opus-4-5-vs-skt-ax)
- [A.X K2 vs Claude Opus 4.5 Thinking](/compare/a-x-k2-vs-claude-opus-4-5-thinking)
- [Claude Opus 4.5 vs Claude Opus 4.5 Thinking](/compare/claude-opus-4-5-vs-claude-opus-4-5-thinking)

## Explore More

- [A.X K2 profile](/models/a-x-k2)
- [Claude Opus 4.5 profile](/models/claude-opus-4-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)