In traditional computers, data is stored as bits, which have a value of either 0 or 1. In a quantum computer, data is stored as qubits, which can exist in multiple states simultaneously. This allows quantum computers to perform certain types of calculations much faster than traditional computers.
The most famous algorithm that is faster in quantum computer is Shor's algorithm for factorizing integers in polynomial time, which is a huge improvement over the best known classical algorithms that run in exponential time. This is why Quantum computers have the potential to revolutionize fields like cryptography and drug discovery. However, quantum computers are still in the early stages of development and it's uncertain when they will be available for general use.
