If I can believe this ( http://www.cryptopp.com/benchmarks.html http://www.cryptopp.com/benchmarks.html ), SHA-512 can still hash data at tens to hundreds of me

If I can believe this ( http://www.cryptopp.com/benchmarks.html http://www.cryptopp.com/benchmarks.html ), SHA-512 can still hash data at tens to hundreds of megabytes per second on a single couple-year-old core. Bcrypt lets you configure the slowness of your key generation with a "work factor", so I suppose with a work factor of 1 it'd probably be pretty fast too, but with a work factor of 10 it takes me roughly 100ms to hash 1 10-byte password. So yeah, SHA-512 gives you a much larger keyspace, which is awesome, but isn't demonstrably slower than MD5, SHA-1, etc. Which was one of its design goals (and also one of the goals of all entrants in the ongoing SHA-3 competition).