Model comparison
Claude Mythos 5 vs Grok Code Fast 1
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Mythos 5 #1 (Supported); Grok Code Fast 1 #180 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Mythos 5 and Grok Code Fast 1 share 1 comparable benchmark result. 1 of 8 categories are comparable. 14 results are unique to Claude Mythos 5; 11 to Grok Code Fast 1.
Updated July 23, 2026- Shared results
- 1
- Claude Mythos 5 only
- 14
- Grok Code Fast 1 only
- 11
- Comparable categories
- 1 / 8
Pick Claude Mythos 5 if you want the stronger benchmark profile. Grok Code Fast 1 only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 1 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 38.64. 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 70.8. The single biggest benchmark swing on the page is SWE-bench Verified, 95.5% to 70.8%.
Claude Mythos 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $0.20 input / $1.50 output per 1M tokens for Grok Code Fast 1. That is roughly 33.3x on output cost alone. Claude Mythos 5 is the reasoning model in the pair, while Grok Code Fast 1 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Claude Mythos 5 gives you the larger context window at 1M+, compared with 256K for Grok Code Fast 1.
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 | Grok Code Fast 1 |
|---|---|---|---|
| Coding | Claude Mythos 589.7 | Margin← 18.9 | Grok Code Fast 170.8 |
| Agentic | Claude Mythos 587.0 | MarginNo overlap | Grok Code Fast 1Not measured |
| Knowledge | Claude Mythos 568.5 | MarginNo overlap | Grok Code Fast 1Not measured |
| Math | Claude Mythos 597.6 | MarginNo overlap | Grok Code Fast 1Not measured |
| Multimodal | Claude Mythos 593.5 | MarginNo overlap | Grok Code Fast 1Not measured |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 95.5%B 70.8%Winner: Claude Mythos 5Δ 24.7SWE-bench Verified: Claude Mythos 5 scored 95.5%; Grok Code Fast 1 scored 70.8%. 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 | Grok Code Fast 1 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Mythos 5$10 input / $50 output | Grok Code Fast 1$0.2 input / $1.5 output | Grok Code Fast 1 has the lower combined listed price. |
| Generation speedtokens per second | Claude Mythos 5Not available | Grok Code Fast 1172 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Mythos 5Not available | Grok Code Fast 12.81 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Mythos 51M+ | Grok Code Fast 1256K | Claude Mythos 5 lists the larger context window. |
Benchmark Deep Dive
Agentic5 benchmarks
CodingClaude Mythos 5 wins4 benchmarks
Reasoning2 benchmarks
Knowledge9 benchmarks
| Benchmark | Claude Mythos 5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| GPQASource | 94.1% | — | Not comparable |
| HLESource | 64.5% | — | Not comparable |
| HLE w/o toolsSource | 59% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 21.6% | Not comparable |
| AA-GPQA DiamondSource | — | 72.7% | Not comparable |
| AA-HLESource | — | 7.5% | Not comparable |
| AA-Omniscience IndexSource | — | -36.0% | Not comparable |
| AA-Omniscience AccuracySource | — | 23.8% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 78.5% | Not comparable |
Math1 benchmarks
| Benchmark | Claude Mythos 5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| USAMO 2026Source | 97.6% | — | Not comparable |
Multilingual1 benchmarks
| Benchmark | Claude Mythos 5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| SWE MultilingualSource | 92.2% | — | Not comparable |
Multimodal3 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude Mythos 5 | Grok Code Fast 1 | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 41.4% | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude Mythos 5 or Grok Code Fast 1?
Claude Mythos 5 is ahead on BenchLM's BenchAlign leaderboard, 83.93 to 38.64. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 95.5% and 70.8%.
Which is better for coding, Claude Mythos 5 or Grok Code Fast 1?
Claude Mythos 5 has the edge for coding in this comparison, averaging 89.7 versus 70.8. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
Related Comparisons
Choose a model with this week’s evidence
Join 2,000+ readers for ranking moves, pricing changes, and the claims that still need proof.
One email each week. Unsubscribe anytime.