# Claude Mythos 5 vs Grok 4.20 > Side-by-side benchmark comparison for Claude Mythos 5 and Grok 4.20 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks. - Canonical page: https://benchlm.ai/compare/claude-mythos-5-vs-grok-4-20-beta - Last updated: September 4, 2026 - Shared sourced benchmarks: 5 - HTML indexing: indexable - Ranking lane: BenchAlign v5 ## Quick Verdict Pick Claude Mythos 5 if you want the stronger benchmark profile. Grok 4.20 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score. ## Summary - Claude Mythos 5 leads overall 85 to 67.01. - The clearest category separation is in multimodal & grounded, where the averages are 85.1 for Claude Mythos 5 and 34.6 for Grok 4.20. - The biggest single benchmark swing is Terminal-Bench 2.0 in Agentic, with scores of 88% and 47.1%. - Grok 4.20 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use. - Grok 4.20 also has the larger context window at 2M. ## Model Snapshot | Property | Claude Mythos 5 | Grok 4.20 | |----------|----------|----------| | Creator | Anthropic | xAI | | Type | Proprietary | Proprietary | | Reasoning | Reasoning | Reasoning | | Context | 1M+ | 2M | | Overall Score | null | 67.01 | | Benchmarks Covered | 15 | 23 | | Pricing (input/output) | $10.00 / $50.00 | $2.00 / $6.00 | ## Category Breakdown ### Agentic - Winner: Coming soon - Claude Mythos 5 public-lane score: Coming soon - Grok 4.20 public-lane score: 26.5 (Supported · #144/151) | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | Terminal-Bench 2.0 | 88% | 47.1% | Claude Mythos 5 | | OSWorld-Verified | 85% | Coming soon | Coming soon | | BrowseComp | 88% | Coming soon | Coming soon | | CyberGym | 83.8% | Coming soon | Coming soon | | DeepSearchQA | Coming soon | 62.8% | Coming soon | | Gert Labs | Coming soon | 38.36% | Coming soon | | Terminal-Bench 2.1 (Vals) | Coming soon | 44.2% | Coming soon | ### Coding - Winner: Coming soon - Claude Mythos 5 public-lane score: Coming soon - Grok 4.20 public-lane score: 28.2 (Supported · #171/183) | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | SWE-bench Verified | 95.5% | 76.7% | Claude Mythos 5 | | SWE-bench Pro | 80.3% | 51.8% | Claude Mythos 5 | | Terminal-Bench 2.0 | 88.0% | Coming soon | Coming soon | | LiveCodeBench Pro | Coming soon | 74.2% | Coming soon | | Vibe Code Bench | Coming soon | 4.06% | Coming soon | | LiveCodeBench (Vals) | Coming soon | 84.3% | Coming soon | | SWE-bench (Vals) | Coming soon | 72.2% | Coming soon | ### Multimodal & Grounded - Winner: Coming soon - Claude Mythos 5 public-lane score: 85.1 (Unranked · 3 rankable rows) - Grok 4.20 public-lane score: 34.6 (#43/48) | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | SWE-bench Multimodal | 54.9% | Coming soon | Coming soon | | CharXiv | 93.5% | 60.9% | Claude Mythos 5 | | CharXiv w/o tools | 88.9% | Coming soon | Coming soon | | MMMU-Pro | Coming soon | 75.2% | Coming soon | | ERQA | Coming soon | 54.1% | Coming soon | | SimpleVQA | Coming soon | 57.4% | Coming soon | | MedXpertQA (MM) | Coming soon | 65.8% | Coming soon | ### Reasoning - Winner: Coming soon - Claude Mythos 5 public-lane score: Coming soon - Grok 4.20 public-lane score: 34.2 (Unranked · 2 rankable rows) | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | ARC-AGI-2 | Coming soon | 53.3% | Coming soon | | ARC-AGI-3 | Coming soon | 0.1% | Coming soon | ### Knowledge - Winner: Coming soon - Claude Mythos 5 public-lane score: Coming soon - Grok 4.20 public-lane score: 48.7 (Supported · #97/181) | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | GPQA | 94.1% | Coming soon | Coming soon | | HLE | 64.5% | Coming soon | Coming soon | | HLE w/o tools | 59% | 31.6% | Claude Mythos 5 | | GPQA-D | Coming soon | 88.5% | Coming soon | | HealthBench Hard | Coming soon | 20.3% | Coming soon | | MedXpertQA (Text) | Coming soon | 50.2% | Coming soon | | GPQA Diamond (Vals) | Coming soon | 88.6% | Coming soon | | MMLU-Pro (Vals) | Coming soon | 86.3% | Coming soon | ### Multilingual - Winner: Coming soon - Claude Mythos 5 public-lane score: Coming soon - Grok 4.20 public-lane score: Coming soon | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | SWE Multilingual | 92.2% | Coming soon | Coming soon | ### Mathematics - Winner: Coming soon - Claude Mythos 5 public-lane score: Coming soon - Grok 4.20 public-lane score: Coming soon | Benchmark | Claude Mythos 5 | Grok 4.20 | Winner | |-----------|-----------|-----------|--------| | USAMO 2026 | 97.6% | Coming soon | Coming soon | ## FAQ ### Which is better overall, Claude Mythos 5 or Grok 4.20? Claude Mythos 5 is ahead overall on BenchLM right now. ### Where is the biggest gap between Claude Mythos 5 and Grok 4.20? The widest category gap is in multimodal & grounded, where the averages are 85.1 for Claude Mythos 5 and 34.6 for Grok 4.20. ### 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 Grok 4.20 cover on BenchLM? Grok 4.20 currently has 23 sourced benchmark scores on BenchLM. ## Related Comparisons - [Claude Mythos 5 vs Claude Mythos 5.1](/compare/claude-mythos-5-vs-claude-mythos-5-1) - [Grok 4.20 vs Claude Mythos 5.1](/compare/claude-mythos-5-1-vs-grok-4-20-beta) - [Claude Mythos 5 vs Claude Mythos Preview](/compare/claude-mythos-5-vs-claude-mythos-preview) - [Grok 4.20 vs Claude Mythos Preview](/compare/claude-mythos-preview-vs-grok-4-20-beta) ## Explore More - [Claude Mythos 5 profile](/models/claude-mythos-5) - [Grok 4.20 profile](/models/grok-4-20-beta) - [Compare Pricing](/llm-pricing) - [Alternative Finder](/tools/alternative-finder) - [LLM Selector](/tools/llm-selector) - [Overall Rankings](/best/overall)