Overview
As transistors get smaller, we can fit more of them on a chip than we can afford to power simultaneously without the chip melting. This 'power wall' means that at any given time, a large percentage of the chip must remain 'dark' (unpowered).
Consequences
- Specialization: Instead of more general-purpose cores, designers add specialized accelerators (for video, AI, etc.) that are only turned on when needed.
- Dim Silicon: Running many cores at a lower frequency rather than a few cores at a high frequency.
- End of Dennard Scaling: Dark silicon is a direct result of the breakdown of Dennard scaling.
Design Strategy
Modern chip design is less about how many transistors you can fit, and more about how you use the limited 'power budget' across the available silicon.