Head-to-head comparison across 4benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Mythos Preview
99
Claude Opus 4.6
92
Verified leaderboard positions: Claude Mythos Preview #1 · Claude Opus 4.6 #2
Pick Claude Mythos Preview if you want the stronger benchmark profile. Claude Opus 4.6 only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Agentic
+9.8 difference
Coding
+19.4 difference
Knowledge
+1.3 difference
Multimodal
+15.4 difference
Claude Mythos Preview
Claude Opus 4.6
$25 / $125
$15 / $75
N/A
40 t/s
N/A
1.78s
1M
1M
Pick Claude Mythos Preview if you want the stronger benchmark profile. Claude Opus 4.6 only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Claude Mythos Preview is clearly ahead on the provisional aggregate, 99 to 92. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Mythos Preview's sharpest advantage is in coding, where it averages 83.8 against 64.4. The single biggest benchmark swing on the page is SWE-bench Pro, 77.8% to 53.4%. Claude Opus 4.6 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.
Claude Mythos Preview is also the more expensive model on tokens at $25.00 input / $125.00 output per 1M tokens, versus $15.00 input / $75.00 output per 1M tokens for Claude Opus 4.6. Claude Mythos Preview is the reasoning model in the pair, while Claude Opus 4.6 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 Preview is ahead on BenchLM's provisional leaderboard, 99 to 92. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 77.8% and 53.4%.
Claude Opus 4.6 has the edge for knowledge tasks in this comparison, averaging 76.2 versus 74.9. Inside this category, HLE w/o tools is the benchmark that creates the most daylight between them.
Claude Mythos Preview has the edge for coding in this comparison, averaging 83.8 versus 64.4. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.
Claude Mythos Preview has the edge for agentic tasks in this comparison, averaging 82.4 versus 72.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Claude Mythos Preview has the edge for multimodal and grounded tasks in this comparison, averaging 92.7 versus 77.3. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
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