# GPT-5.3 Codex vs Solar Open 2

> Side-by-side benchmark comparison for GPT-5.3 Codex and Solar Open 2 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-3-codex-vs-solar-open-2
- 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: GPT-5.3 Codex and Solar Open 2 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.
- Solar Open 2 has the lower published output-token price.
- Solar Open 2 has the larger published context window at 1M.

## Model Snapshot

| Property | GPT-5.3 Codex | Solar Open 2 |
|----------|----------|----------|
| Creator | OpenAI | Upstage |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 1M |
| Independent public score (not head-to-head) | 64.29 | null |
| Benchmarks Covered | 8 | 11 |
| Pricing (input/output) | $1.75 / $14.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 61.6 (Estimated · #15/152)
- Solar Open 2 public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Solar Open 2 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 77.3% | Coming soon | Coming soon |
| OSWorld-Verified | 64.7% | Coming soon | Coming soon |
| Gert Labs | 57.47% | Coming soon | Coming soon |
| JobBench | 33.7% | Coming soon | Coming soon |
| terminalBenchHard | Coming soon | 28.3% | Coming soon |
| APEX-Agents | Coming soon | 16.6% | Coming soon |
| MCP Atlas | Coming soon | 58.2% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 62 (Estimated · #17/151)
- Solar Open 2 public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Solar Open 2 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85% | 70.4% | GPT-5.3 Codex |
| SWE-bench Pro | 56.8% | Coming soon | Coming soon |
| SWE-Rebench | 58.2% | Coming soon | Coming soon |
| Vibe Code Bench | 61.77% | Coming soon | Coming soon |
| LiveCodeBench v6 | Coming soon | 92.4% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 75.6 (Unranked · 1 rankable row)
- Solar Open 2 public-lane score: Coming soon

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 78.3 (Unranked · 2 rankable rows)
- Solar Open 2 public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 65.6 (Estimated · #23/183)
- Solar Open 2 public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Solar Open 2 | Winner |
|-----------|-----------|-----------|--------|
| MMLU-Pro | Coming soon | 86.2% | Coming soon |
| GPQA-D | Coming soon | 86.3% | Coming soon |
| HLE w/o tools | Coming soon | 28.8% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 92.6 (#15/123)
- Solar Open 2 public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Solar Open 2 | Winner |
|-----------|-----------|-----------|--------|
| IFBench | Coming soon | 80% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: Coming soon
- Solar Open 2 public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Solar Open 2 | Winner |
|-----------|-----------|-----------|--------|
| HMMT Feb 2026 | Coming soon | 93.9% | Coming soon |
| AIME26 | Coming soon | 95.7% | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-5.3 Codex and Solar Open 2?

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

- [GPT-5.3 Codex vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-vs-gpt-5-3-codex-spark)
- [Solar Open 2 vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-spark-vs-solar-open-2)
- [GPT-5.3 Codex vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gpt-5-3-codex)
- [Solar Open 2 vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-solar-open-2)

## Explore More

- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Solar Open 2 profile](/models/solar-open-2)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)