Head-to-head comparison across 3benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Claude Mythos Preview
99
Qwen3.5-27B
62
Verified leaderboard positions: Claude Mythos Preview #1 · Qwen3.5-27B #18
Pick Claude Mythos Preview if you want the stronger benchmark profile. Qwen3.5-27B only becomes the better choice if knowledge is the priority or you want the cheaper token bill.
Agentic
+30.8 difference
Coding
+20.8 difference
Knowledge
+5.7 difference
Claude Mythos Preview
Qwen3.5-27B
$25 / $125
$0 / $0
N/A
N/A
N/A
N/A
1M
262K
Pick Claude Mythos Preview if you want the stronger benchmark profile. Qwen3.5-27B 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 62. 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 agentic, where it averages 82.4 against 51.6. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 82% to 41.6%. Qwen3.5-27B 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 $0.00 input / $0.00 output per 1M tokens for Qwen3.5-27B. That is roughly Infinityx on output cost alone. Claude Mythos Preview gives you the larger context window at 1M, compared with 262K for Qwen3.5-27B.
Claude Mythos Preview is ahead on BenchLM's provisional leaderboard, 99 to 62. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 82% and 41.6%.
Qwen3.5-27B has the edge for knowledge tasks in this comparison, averaging 80.6 versus 74.9. Inside this category, GPQA 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 63. Inside this category, SWE-bench Verified 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 51.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
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