Claude Mythos 5 vs Claude Opus 4.8 — Who Actually Wins? Real Benchmark Data (2026)

head to head

Claude Mythos 5 vs Claude Opus 4.8

5 shared benchmarks

5

wins

0

ties

0

wins

88.0%

BrowseComp

84.3%

94.1%

GPQA Diamond

91.0%

80.3%

SWE-bench Pro

69.2%

88.0%

Terminal-Bench 2.1

84.6%

61.7%

Toolathlon

59.9%