Is there any advantage to using the AVX2 version instead of the legacy x64?

[MagicalDrizzle]

It seems the only difference is AVX2 requires Haswell+/Excavator+ and Windows 7+
Is there any performance difference?

[zufuliu]

AVX2 version is faster for large file, you can search NP2_USE_AVX2 in the code.

[MagicalDrizzle]

I see, then is there any difference between the compilers used? (gcc/msvc19/22/clang etc)

[zufuliu]

The obvious difference is binary size (MSVC produces small binary than Clang/GCC), speed differences is not measured.