From my fuzzy memory: To make a cpu fast you need to shrink them. To the point that the "wires" in the core are so close together that electrons jump from one

From my fuzzy memory: To make a cpu fast you need to shrink them. To the point that the "wires" in the core are so close together that electrons jump from one another. So there is lots of electrical interference. To overcome this voltage needs to be increased. This takes more power and makes the cpu hotter (which requires cooling). But dont take my word for it. I did some quick Googling. Maybe you can find some better source and explanation: https://en.wikipedia.org/wiki/Multi-core_processor#Technical_factors https://en.wikipedia.org/wiki/Multi-core_processor#Technical... "For general-purpose processors, much of the motivation for multi-core processors comes from greatly diminished gains in processor performance from increasing the operating frequency. This is due to three primary factors: - The memory wall; [...] - The ILP wall; [...] - The power wall; the trend of consuming exponentially increasing power with each factorial increase of operating frequency. This increase can be mitigated by "shrinking" the processor by using smaller traces for the same logic. The power wall poses manufacturing, system design and deployment problems that have not been justified in the face of the diminished gains in performance due to the memory wall and ILP wall."