Hardware that has more memory, more processing speed, faster access to memory, and more parallelism is better than hardware without those characteristics.

The exact same software running on better hardware will run faster and can tackle larger problems.

We can't possibly build a human with twice the memory that thinks twice as fast. However once we have an AI which is roughly equivalent to a human, having an AI with twice as much memory that thinks twice as fast is just 2-5 years. (How long depends on where the bottleneck is.)