I am a layman when it comes to quantum computing, but I have heard it described similarly to the jump in register size in traditional computers. Every bit you add doubles the computing power and addressable memory.

So a 16 bit computer is orders of magnitude more capable than an 8 bit computer and our current generation of 64 bit computers are orders of magnitude over that.

With quantum computers instead of each additional bit increasing capacity by the power of 2, it is increased by the power of 6 (as it was explained to me at the time). So a 16 Qbit quantum computer would theoretically outperform an equivalent clock speed 64 bit digital computer.

This could be incorrect, but it was how it was presented to me by someone who works in the field.