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

head to head

Claude Mythos Preview vs GPT-5.4 Nano

4 shared benchmarks

4

wins

0

ties

0

wins

94.6%

GPQA Diamond

82.8%

79.6%

OSWorld

39.0%

77.8%

SWE-bench Pro

52.4%

82.0%

Terminal-Bench 2.0

46.3%