# Claude Mythos 5 vs Ornith-1.5-397B

> Side-by-side benchmark comparison for Claude Mythos 5 and Ornith-1.5-397B across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-mythos-5-vs-ornith-1-5-397b
- Last updated: October 2, 2026

- Shared sourced benchmarks: 8
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Claude Mythos 5 leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Claude Mythos 5 has the higher overall point estimate 84 to 62.72. Conditional score ranges do not establish rank confidence.
- The biggest single benchmark swing is HLE in Knowledge, with scores of 64.5% and 44.6%.
- Ornith-1.5-397B is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Claude Mythos 5 also has the larger context window at 1M+.

## Model Snapshot

| Property | Claude Mythos 5 | Ornith-1.5-397B |
|----------|----------|----------|
| Creator | Anthropic | Ornith AI |
| Type | Proprietary | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M+ | 262K |
| Overall Score | null | 62.72 |
| Benchmarks Covered | 15 | 18 |
| Pricing (input/output) | $10.00 / $50.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: 56.8 (Estimated · #29/119)

| Benchmark | Claude Mythos 5 | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 88.0% | 86.1% | Claude Mythos 5 |
| OSWorld-Verified | 85% | Coming soon | Coming soon |
| BrowseComp | 88% | 86.6% | Claude Mythos 5 |
| CyberGym | 83.8% | Coming soon | Coming soon |
| HLE w/ tools | Coming soon | 56.1% | Coming soon |
| MCP Atlas | Coming soon | 80% | Coming soon |
| Toolathlon-Verified | Coming soon | 71.2% | Coming soon |
| WideResearch | Coming soon | 80.8% | Coming soon |
| Claw-Eval | Coming soon | 81.4% | Coming soon |

### Coding

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: 54.7 (Estimated · #34/144)

| Benchmark | Claude Mythos 5 | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 95.5% | 86% | Claude Mythos 5 |
| SWE-bench Pro | 80.3% | 65.1% | Claude Mythos 5 |
| Terminal-Bench 2.1 | 88.0% | 86.1% | Claude Mythos 5 |
| SWE Multilingual | Coming soon | 79.6% | Coming soon |
| DeepSWE | Coming soon | 56.0% | Coming soon |
| frontierBench | Coming soon | 13.5% | Coming soon |
| NL2Repo | Coming soon | 59.5% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Mythos 5 public-lane score: 86.2 (Unranked · 3 rankable rows)
- Ornith-1.5-397B public-lane score: Coming soon

| Benchmark | Claude Mythos 5 | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Multimodal | 54.9% | Coming soon | Coming soon |
| CharXiv | 93.5% | Coming soon | Coming soon |
| CharXiv w/o tools | 88.9% | Coming soon | Coming soon |

### Knowledge

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: 63.3 (Estimated · #36/171)

| Benchmark | Claude Mythos 5 | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 94.1% | 92.8% | Claude Mythos 5 |
| HLE | 64.5% | 44.6% | Claude Mythos 5 |
| HLE w/o tools | 59% | 44.6% | Claude Mythos 5 |
| GPQA-D | Coming soon | 92.8% | Coming soon |

### Multilingual

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: Coming soon

| Benchmark | Claude Mythos 5 | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| SWE Multilingual | 92.2% | Coming soon | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Mythos 5 public-lane score: Coming soon
- Ornith-1.5-397B public-lane score: Coming soon

| Benchmark | Claude Mythos 5 | Ornith-1.5-397B | Winner |
|-----------|-----------|-----------|--------|
| USAMO 2026 | 97.6% | Coming soon | Coming soon |

## FAQ

### Which is better overall, Claude Mythos 5 or Ornith-1.5-397B?

Claude Mythos 5 has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

### How many benchmarks does Claude Mythos 5 cover on BenchLM?

Claude Mythos 5 currently has 15 sourced benchmark scores on BenchLM.

### How many benchmarks does Ornith-1.5-397B cover on BenchLM?

Ornith-1.5-397B currently has 18 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Mythos 5 vs Claude Mythos 5.1](/compare/claude-mythos-5-vs-claude-mythos-5-1)
- [Ornith-1.5-397B vs Claude Mythos 5.1](/compare/claude-mythos-5-1-vs-ornith-1-5-397b)
- [Claude Mythos 5 vs Claude Mythos Preview](/compare/claude-mythos-5-vs-claude-mythos-preview)
- [Ornith-1.5-397B vs Claude Mythos Preview](/compare/claude-mythos-preview-vs-ornith-1-5-397b)

## Explore More

- [Claude Mythos 5 profile](/models/claude-mythos-5)
- [Ornith-1.5-397B profile](/models/ornith-1-5-397b)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)