It seems kind of an inelegant solution to me. They could just solder a resistor to the package at the factory or do some variation of that idea. Now, modern pr

It seems kind of an inelegant solution to me. They could just solder a resistor to the package at the factory or do some variation of that idea. Now, modern processors are binned, too, depending on the CMOS process corner they turned at. Slow ones have advantages too - leakage is much smaller, so better suited for mobile. Or, in case of some SoC, if it's FF (fast NMOS, fast PMOS), they can reduce core supply by tens of mV. There's even a company specialized in PVT (process, voltage, temperature) monitoring for newest SoC's - Moortec.