Unrelated to the post's point but: Why does x86 build faster than x86_64? Presumably they used the same exact hardware, or at least the exact same number of cor

Unrelated to the post's point but: Why does x86 build faster than x86_64? Presumably they used the same exact hardware, or at least the exact same number of cores and memory, yet the build time is more than 10% faster in x86. Is there some sort of overhead for x86_64 that I'm not seeing?