further:
http://stackoverflow.com/a/1561245/404019 http://en.wikipedia.org/wiki/Bcrypt
... i can't find any literature suggesting sha512 decreases your security, and no reason to bother switching. both are good solutions.
This is interesting WRT memory usage. Whether it's a reason to bother switching or coding in the first place is still debatable of course.
http://www.h-online.com/security/news/item/John-the-Ripper-now-able-to-crack...