| This is where I believe the author goes astray: "Despite TSMC claiming a 1.8x shrink for N5, Apple only achieves a 1.49x shrink." TSMC does NOT say they have a 1.8x shrink for N5, they say for LOGIC you can get that, but for SRAM and Analog the results are 1.35x and 1.2x. Had they summed that together for a "typical SOC", which they also discuss (and one presumes that Apple makes typical SOCs) then the "theoretical" shrink is 1.57x for SoCs. The challenge is that whereas at one time the node size was that of a "gate" (which could be 4 transistors), in a marketing race for smaller numbers fabs started emphasizing "feature" size. Because of this change, the "theoretical shrink" is a function of what kinds of circuits you're putting down. Pure logic? You get one number, two gates connected together for a flip-flop, you get another number, a voltage regulator, or ADC filter, you get another number. So doing the analysis the author claims to do, can ONLY be done if you know what percentage of the part you are making on the new process is what. I am under the impression that they missed that. |