Model comparison
Claude Mythos 5 vs Claude Opus 4.8
Head-to-head evidence from 12 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Mythos 5 #2 (Supported); Claude Opus 4.8 #6 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Mythos 5 and Claude Opus 4.8 share 12 comparable benchmark results. 5 of 8 categories are comparable. 3 results are unique to Claude Mythos 5; 43 to Claude Opus 4.8.
Updated July 24, 2026- Shared results
- 12
- Claude Mythos 5 only
- 3
- Claude Opus 4.8 only
- 43
- Comparable categories
- 5 / 8
Pick Claude Mythos 5 if you want the stronger benchmark profile. Claude Opus 4.8 only becomes the better choice if you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 12 shared benchmark results across 5 evidence categories; 5 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, 83.01 to 77.44. 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 mathematics, where it averages 97.6 against 53.9. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 88% to 74.6%.
Claude Mythos 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $5.00 input / $25.00 output per 1M tokens for Claude Opus 4.8. That is roughly 2.0x on output cost alone. Claude Mythos 5 gives you the larger context window at 1M+, compared with 1M for Claude Opus 4.8.
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 | Claude Opus 4.8 |
|---|---|---|---|
| Math | Claude Mythos 597.6 | Margin← 43.7 | Claude Opus 4.853.9 |
| Multimodal | Claude Mythos 593.5 | Margin← 16.5 | Claude Opus 4.877.0 |
| Coding | Claude Mythos 589.7 | Margin← 8.6 | Claude Opus 4.881.1 |
| Agentic | Claude Mythos 587.0 | Margin← 6.7 | Claude Opus 4.880.3 |
| Knowledge | Claude Mythos 568.5 | Margin← 5.8 | Claude Opus 4.862.7 |
| Reasoning | Claude Mythos 5Not measured | MarginNo overlap | Claude Opus 4.872.1 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
Terminal-Bench 2.0
AgenticA 88%B 74.6%Winner: Claude Mythos 5Δ 13.4Terminal-Bench 2.0: Claude Mythos 5 scored 88%; Claude Opus 4.8 scored 74.6%. Claude Mythos 5 wins this benchmark. - Source ↗
SWE-bench Pro
CodingA 80.3%B 69.2%Winner: Claude Mythos 5Δ 11.1SWE-bench Pro: Claude Mythos 5 scored 80.3%; Claude Opus 4.8 scored 69.2%. Claude Mythos 5 wins this benchmark. - Source ↗
SWE-bench Verified
CodingA 95.5%B 88.6%Winner: Claude Mythos 5Δ 6.9SWE-bench Verified: Claude Mythos 5 scored 95.5%; Claude Opus 4.8 scored 88.6%. Claude Mythos 5 wins this benchmark. - Source ↗
HLE
KnowledgeA 64.5%B 57.9%Winner: Claude Mythos 5Δ 6.6HLE: Claude Mythos 5 scored 64.5%; Claude Opus 4.8 scored 57.9%. Claude Mythos 5 wins this benchmark. - Source ↗
BrowseComp
AgenticA 88%B 84.3%Winner: Claude Mythos 5Δ 3.7BrowseComp: Claude Mythos 5 scored 88%; Claude Opus 4.8 scored 84.3%. 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 | Claude Opus 4.8 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Mythos 5$10 input / $50 output | Claude Opus 4.8$5 input / $25 output | Claude Opus 4.8 has the lower combined listed price. |
| Generation speedtokens per second | Claude Mythos 5Not available | Claude Opus 4.8Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Mythos 5Not available | Claude Opus 4.8Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Mythos 51M+ | Claude Opus 4.81M | Claude Mythos 5 lists the larger context window. |
Benchmark Deep Dive
AgenticClaude Mythos 5 wins22 benchmarks
| Benchmark | Claude Mythos 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 88% | 74.6% | Claude Mythos 5 leads |
| OSWorld-VerifiedSource | 85% | 83.4% | Claude Mythos 5 leads |
| BrowseCompSource | 88% | 84.3% | Claude Mythos 5 leads |
| ExploitGymSource | 17.5% | — | Not comparable |
| DeepSearchQASource | — | 93.1% | Not comparable |
| Finance Agent v2Source | — | 53.9% | Not comparable |
| GDPval-AASource | — | 1593 | Not comparable |
| MCP AtlasSource | — | 82.2% | Not comparable |
| ToolathlonSource | — | 59.9% | Not comparable |
| Gert LabsSource | — | 72.97% | Not comparable |
| AA Agentic IndexSource | — | 47.2% | Not comparable |
| τ²-bench resultsSource | — | 94.4% | Not comparable |
| GDPval-AASource | — | 54.6% | Not comparable |
| ResearchClawBenchSource | — | 21.1% | Not comparable |
| OSWorld 2.0Source | — | 20.6% | Not comparable |
| AA BriefcaseSource | — | 1346 | Not comparable |
| AA AutomationBenchSource | — | 48.5% | Not comparable |
| AA EnterpriseOps-GymSource | — | 44.0% | Not comparable |
| AA Harvey LABSource | — | 91.1% | Not comparable |
| AA Tau3 BankingSource | — | 27.6% | Not comparable |
| terminalBenchHardSource | — | 58.3% | Not comparable |
| aaTerminalBench21Source | — | 84.6% | Not comparable |
CodingClaude Mythos 5 wins10 benchmarks
| Benchmark | Claude Mythos 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 95.5% | 88.6% | Claude Mythos 5 leads |
| SWE-bench ProSource | 80.3% | 69.2% | Claude Mythos 5 leads |
| Terminal-Bench 2.0Source | 88.0% | 74.6% | Claude Mythos 5 leads |
| SWE MultilingualSource | — | 84.4% | Not comparable |
| SWE MultimodalSource | — | 38.4% | Not comparable |
| cursorBench31Source | — | 58.4% | Not comparable |
| cursorBench32Source | — | 62.3% | Not comparable |
| AA Coding IndexSource | — | 74.3% | Not comparable |
| AA-SciCodeSource | — | 53.5% | Not comparable |
| FrontierCode 1.1 MainSource | — | 46.5% | Not comparable |
Reasoning4 benchmarks
KnowledgeClaude Mythos 5 wins10 benchmarks
| Benchmark | Claude Mythos 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| GPQASource | 94.1% | 93.6% | Claude Mythos 5 leads |
| HLESource | 64.5% | 57.9% | Claude Mythos 5 leads |
| HLE w/o toolsSource | 59% | 49.8% | Claude Mythos 5 leads |
| GPQA-DSource | — | 93.6% | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 55.7% | Not comparable |
| AA-GPQA DiamondSource | — | 92.0% | Not comparable |
| AA-HLESource | — | 45.7% | Not comparable |
| AA-Omniscience IndexSource | — | 27.4% | Not comparable |
| AA-Omniscience AccuracySource | — | 46.6% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 35.9% | Not comparable |
MathClaude Mythos 5 wins3 benchmarks
Multilingual2 benchmarks
MultimodalClaude Mythos 5 wins6 benchmarks
| Benchmark | Claude Mythos 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| SWE-bench MultimodalSource | 54.9% | — | Not comparable |
| CharXivSource | 93.5% | 89.9% | Claude Mythos 5 leads |
| CharXiv w/o toolsSource | 88.9% | 80.5% | Claude Mythos 5 leads |
| OfficeQA ProSource | — | 66.2% | Not comparable |
| ScreenSpot ProSource | — | 87.9% | Not comparable |
| Design Arena WebsiteSource | — | 1270 | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Claude Mythos 5 | Claude Opus 4.8 | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 62.2% | Not comparable |
Frequently Asked Questions (6)
Which is better, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 is ahead on BenchLM's BenchAlign leaderboard, 83.01 to 77.44. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 88% and 74.6%.
Which is better for knowledge tasks, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 has the edge for knowledge tasks in this comparison, averaging 68.5 versus 62.7. Inside this category, HLE w/o tools is the benchmark that creates the most daylight between them.
Which is better for coding, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 has the edge for coding in this comparison, averaging 89.7 versus 81.1. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Which is better for math, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 has the edge for math in this comparison, averaging 97.6 versus 53.9. Inside this category, USAMO 2026 is the benchmark that creates the most daylight between them.
Which is better for agentic tasks, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 has the edge for agentic tasks in this comparison, averaging 87 versus 80.3. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Which is better for multimodal and grounded tasks, Claude Mythos 5 or Claude Opus 4.8?
Claude Mythos 5 has the edge for multimodal and grounded tasks in this comparison, averaging 93.5 versus 77. Inside this category, CharXiv w/o tools is the benchmark that creates the most daylight between them.