In search of platform independent 128-bit hash function
If the space of inputs is predetermined before you deploy your system, you can create a perfect hash that is very fast to evaluate and guarantees unique hash values, such as with gperf or nbperf.

If the space of inputs is chosen by a non-adaptive adversary—i.e., an adversary picks a set of keys and then feeds them all to your system at once without picking some keys based on how the system reacted to others—then you can pick some (almost-)universal hash family such as Poly1305 with a secret key you choose uniformly at random: for any pair of inputs, the probability over all possible keys that the inputs collide is $O(1/m)$, where $m$ is the number of possible hash values.

If the space of inputs is chosen by an adaptive adversary and Siphash is too slow, you will need to describe your performance budget in more detail:


How many keys do you have?
What is the distribution of key lengths?
How many cycles per byte can you afford?
How many cycles per key can you afford?
How many bytes can you afford to transmit/store?
What is the cost of a collision?  Of $n$ collisions?


(Transmitting 8 bytes on a network is not free!  Exercise for the reader: How many nanoseconds and joules does it take to compute Siphash on a 16-byte input on your laptop's CPU, and how many nanoseconds and joules does it take your  laptop's ethernet phy to transmit 8 bytes?)