Claude Mythos Preview vs GPT-5.4 — Who Actually Wins? Real Benchmark Data (2026)

head to head

Claude Mythos Preview vs GPT-5.4

8 shared benchmarks

8

wins

0

ties

0

wins

86.9%

BrowseComp

82.7%

94.6%

GPQA Diamond

92.8%

56.8%

Humanity's Last Exam

36.24%

79.6%

OSWorld

75.0%

77.8%

SWE-bench Pro

57.7%

93.9%

SWE-bench Verified

77.2%

82.0%

Terminal-Bench 2.0

81.8%

97.6%

USAMO 2026

95.2%