SHA-512 provides a higher security level (256 bits), but there's not much practical value in a security level higher than 128 bits. I think "better" is too stro

SHA-512 provides a higher security level (256 bits), but there's not much practical value in a security level higher than 128 bits. I think "better" is too strong a word here. SHA-512 is faster than SHA-256 in software on 64-bit machines. That's a more important difference than the security level. However, there are two major caveats to consider: 1) Hash function performance is more likely to matter on cheap (non-64-bit) hardware where everything is slow, than on fancy hardware where everything is fast. 2) Some x86 and ARM chips have hardware accelerated implementations of SHA-256, but not of SHA-512.