The point being: A lot of code running on CPUs is incredibly inefficient today. The first step towards efficiency is to make good use of the platforms we have already. That has been the focus of this class so far. However, even if we've tuned your software to get all we can out of a modern multi-core CPU (or maybe a more throughput-optimized GPU), the applications of the future will still will be hungry for increasingly greater performance and energy efficiency.
To make the next big steps towards highly efficient computing, we'll need to begin thinking about more efficient hardware platforms than just multi-core CPUs or GPUs. And that's what today's lecture is about.