My results similar with M4 Pro (12 cores, 16 cores GPU), 24 GB RAM macOS 26.2 (the same benchmarks, I guess, https://browserbench.org/JetStream2.0/):

Firefox: 298.136

Safari: 425.762

Just the last test in this test suite:

> 3d-cube-SP > 3D cube rotation benchmark by Simon Speich. The original can be found on Simon's web page. Tests arrays and floating-point math in relatively short-running code.

gives the following results:

Firefox: 305.197

200 First 338.983 Worst 419.309 Average

Safari: 818.449

238.095 First 176.471 Worst 1957.237 Average

which shows that in this particular test, Safari is 2.5 times faster.