There is a one-to-one relationship between the number of transistors a microprocessor has and its processing power. The potential power of a classical computer doubles every time you double the number of transistors.
In a quantum system, the rough equivalent of a transistor is something called a quantum bit, or a qubit. But there’s a big difference. The potential power of a quantum computer doubles every time you add one additional qubit.
Learn more about quantum computing and IBM Q at https://www.research.ibm.com/ibm-q/.