https://arstechnica.com/gadgets/2023/11/testing-apples-m3-pro-more-efficient-but-performance-is-a-step-sideways/

When Apple announced the first three chips in its M3 processor family, the M3 Pro immediately stood out. Not because it was a huge leap over the prior generation, but because it was the first time we had seen Apple reduce key specs like transistor count, CPU and GPU core count, and memory bandwidth from one generation to the next.

Transistor count is an imperfect proxy for performance, but adding transistors is one of the primary ways to improve a chip's performance (ramping clock speeds up is another, which we'll revisit shortly). Both the M3 and M3 Max feature substantial transistor count boosts compared to their M2 counterparts—from 20 billion to 25 billion for the M3, and from 67 billion to 92 billion with the M3 Max. The M3 Pro has 37 billion, down from 40 billion in the M2 Pro.