[hajile]

What is the tradeoff? Cryptographically secure hashes usually require dozens of rounds and take a lot of time. Could two less secure hashes could do the same thing in less time? What about when the crypto hash is hardware accelerated?

I haven't run the numbers, but I'd bet that two easy hashes still beat the hardware accelerated one by quite a lot (taking time is part of what makes cryptographic hashes secure).