Is Threadripper the fastest CPU?

As of now ( Nov 2021 ) Threadrippers are the highest AMD Ryzen CPUs available. They are categorized as either HEDT ( High-End Desktop ) or Workstation CPUs. Depending on the specific use case some Intel CPUs may be able to compete. If you want the best CPU from AMD you are going to end up getting one of these. There are several different Threadrippers available in each generation so you will need to decide which you want.

If you care more about cores and parallel processing than you do about single core performance then the Thread ripper becomes even more of a clear winner.

If Apple releases more powerful M1 ( or M2 ) processors when the new Mac Pros are released, they may be able to surpass even the fastest thread rippers. They are already better in terms of power consumption but if you want pure processing power you will get more of it with the newer Threadrippers.