The number of collisions is only loosely based on the hash function, it's much more closely tied to the fill factor. If you keep your hash table 1% full then y

The number of collisions is only loosely based on the hash function, it's much more closely tied to the fill factor. If you keep your hash table 1% full then you're unlikely to run into a collision no matter how bad your hash function is. If you keep your table 99% full then it doesn't matter how good your hash function is. You still have to modulo your hash by the number of buckets.