@User @User the 1.8V Sky130 Fets are not that slow. A 7 stage ring oscillator at 1.8V, 25C, tt process corner shows 37.5ps inverter delay (1/0.15 N, 2/0.15 P, 4fF stage output parax cap.) ... Someone has some benchmark data to verify if this data is reasonable?

I simulated about the same number of inverter stages using the HS mux2i cell and got similar numbers ~1GHz. I am not sure this is a validating number since we are using essentially the same transistor models.

Thanks at least there is an alignment. 👍