I'm not an expert on this but my understanding is that it's not the speed of a hash function that determines its security, because once an adversary is trying t

I'm not an expert on this but my understanding is that it's not the speed of a hash function that determines its security, because once an adversary is trying to brute-force a hash function you can just increase the length of the hash. The speed of the hash function is polynomial in the length of the output, but the cost of brute forcing is exponential in the length of the output, so if you have a faster hash function (or a faster processor) you can increase the size of the output by a constant multiple, and increase the cost of brute-forcing by an exponential amount, keeping the hash function secure. But I could be totally off-base here.