# A.X K2 vs GPT-5.5 Pro

> Side-by-side benchmark comparison for A.X K2 and GPT-5.5 Pro across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

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

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: A.X K2 and GPT-5.5 Pro share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- A.X K2 has the lower published output-token price.
- GPT-5.5 Pro has the larger published context window at 1M.

## Model Snapshot

| Property | A.X K2 | GPT-5.5 Pro |
|----------|----------|----------|
| Creator | SK Telecom | OpenAI |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 262K | 1M |
| Independent public score (not head-to-head) | null | 61.32 |
| Benchmarks Covered | 10 | 6 |
| Pricing (input/output) | $0.00 / $0.00 | $30.00 / $180.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- A.X K2 public-lane score: Coming soon
- GPT-5.5 Pro public-lane score: 58.4 (Estimated · #29/152)

| Benchmark | A.X K2 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 36.0% | Coming soon | Coming soon |
| BrowseComp | Coming soon | 90.1% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- A.X K2 public-lane score: Coming soon
- GPT-5.5 Pro public-lane score: Coming soon

| Benchmark | A.X K2 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench v6 | 84.0% | Coming soon | Coming soon |
| SciCode | 41% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 36.0% | Coming soon | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- A.X K2 public-lane score: Coming soon
- GPT-5.5 Pro public-lane score: 58.9 (Estimated · #39/183)

| Benchmark | A.X K2 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| HLE | 27.8% | 57.2% | GPT-5.5 Pro |
| GPQA-D | 85.6% | Coming soon | Coming soon |
| HLE w/o tools | Coming soon | 43.1% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- A.X K2 public-lane score: Coming soon
- GPT-5.5 Pro public-lane score: Coming soon

| Benchmark | A.X K2 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| IFBench | 75.9% | Coming soon | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- A.X K2 public-lane score: Coming soon
- GPT-5.5 Pro public-lane score: 70.2 (Unranked · 3 rankable rows)

| Benchmark | A.X K2 | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | 97.1% | Coming soon | Coming soon |
| Apex | 45.8% | Coming soon | Coming soon |
| Apex Shortlist | 88.6% | Coming soon | Coming soon |
| FrontierMath (legacy) | Coming soon | 52.4% | Coming soon |
| FrontierMath v2 (Tiers 1-3) | Coming soon | 51.000% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 39.600% | Coming soon |

## FAQ

### Is there enough evidence to pick between A.X K2 and GPT-5.5 Pro?

Not yet. The models share only 1 sourced benchmark row, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [A.X K2 vs A.X series](/compare/a-x-k2-vs-skt-ax)
- [GPT-5.5 Pro vs A.X series](/compare/gpt-5-5-pro-vs-skt-ax)
- [A.X K2 vs GPT-5.5](/compare/a-x-k2-vs-gpt-5-5)
- [GPT-5.5 Pro vs GPT-5.5](/compare/gpt-5-5-vs-gpt-5-5-pro)

## Explore More

- [A.X K2 profile](/models/a-x-k2)
- [GPT-5.5 Pro profile](/models/gpt-5-5-pro)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)