Model comparison
Claude Mythos 5 vs o3-mini
Head-to-head evidence from 2 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Mythos 5 #1 (Supported); o3-mini #136 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Mythos 5 and o3-mini share 2 comparable benchmark results. 2 of 8 categories are comparable. 13 results are unique to Claude Mythos 5; 8 to o3-mini.
Updated July 23, 2026- Shared results
- 2
- Claude Mythos 5 only
- 13
- o3-mini only
- 8
- Comparable categories
- 2 / 8
Pick Claude Mythos 5 if you want the stronger benchmark profile. o3-mini only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 2 shared benchmark results across 2 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Claude Mythos 5 is clearly ahead on the BenchAlign aggregate, 83.93 to 47.41. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Mythos 5's sharpest advantage is in coding, where it averages 89.7 against 49.3. The single biggest benchmark swing on the page is SWE-bench Verified, 95.5% to 49.3%. o3-mini does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
Claude Mythos 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $1.10 input / $4.40 output per 1M tokens for o3-mini. That is roughly 11.4x on output cost alone. Claude Mythos 5 gives you the larger context window at 1M+, compared with 200K for o3-mini.
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 | Claude Mythos 5 | Δ | o3-mini |
|---|---|---|---|
| Coding | Claude Mythos 589.7 | Margin← 40.4 | o3-mini49.3 |
| Knowledge | Claude Mythos 568.5 | Margin→ 8.7 | o3-mini77.2 |
| Agentic | Claude Mythos 587.0 | MarginNo overlap | o3-miniNot measured |
| Math | Claude Mythos 597.6 | MarginNo overlap | o3-miniNot measured |
| Multimodal | Claude Mythos 593.5 | MarginNo overlap | o3-miniNot measured |
| Inst. Following | Claude Mythos 5Not measured | MarginNo overlap | o3-mini93.9 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 95.5%B 49.3%Winner: Claude Mythos 5Δ 46.2SWE-bench Verified: Claude Mythos 5 scored 95.5%; o3-mini scored 49.3%. Claude Mythos 5 wins this benchmark. - Source ↗
GPQA
KnowledgeA 94.1%B 77.2%Winner: Claude Mythos 5Δ 16.9GPQA: Claude Mythos 5 scored 94.1%; o3-mini scored 77.2%. Claude Mythos 5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Mythos 5 | o3-mini | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Mythos 5$10 input / $50 output | o3-mini$1.1 input / $4.4 output | o3-mini has the lower combined listed price. |
| Generation speedtokens per second | Claude Mythos 5Not available | o3-mini160 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Mythos 5Not available | o3-mini7.12 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Mythos 51M+ | o3-mini200K | Claude Mythos 5 lists the larger context window. |
Benchmark Deep Dive
Agentic5 benchmarks
CodingClaude Mythos 5 wins4 benchmarks
Knowledgeo3-mini wins7 benchmarks
| Benchmark | Claude Mythos 5 | o3-mini | Result |
|---|---|---|---|
| GPQASource | 94.1% | 77.2% | Claude Mythos 5 leads |
| HLESource | 64.5% | — | Not comparable |
| HLE w/o toolsSource | 59% | — | Not comparable |
| MMLUSource | — | 86.9% | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 19.0% | Not comparable |
| AA-GPQA DiamondSource | — | 74.8% | Not comparable |
| AA-HLESource | — | 8.7% | Not comparable |
Math2 benchmarks
Multilingual1 benchmarks
| Benchmark | Claude Mythos 5 | o3-mini | Result |
|---|---|---|---|
| SWE MultilingualSource | 92.2% | — | Not comparable |
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude Mythos 5 | o3-mini | Result |
|---|---|---|---|
| IFEvalSource | — | 93.9% | Not comparable |
Frequently Asked Questions (3)
Which is better, Claude Mythos 5 or o3-mini?
Claude Mythos 5 is ahead on BenchLM's BenchAlign leaderboard, 83.93 to 47.41. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 95.5% and 49.3%.
Which is better for knowledge tasks, Claude Mythos 5 or o3-mini?
o3-mini has the edge for knowledge tasks in this comparison, averaging 77.2 versus 68.5. Inside this category, GPQA is the benchmark that creates the most daylight between them.
Which is better for coding, Claude Mythos 5 or o3-mini?
Claude Mythos 5 has the edge for coding in this comparison, averaging 89.7 versus 49.3. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
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