One lecture from 2004 discusses the buffered clock tree in the Alpha 21064 (1992), while the 386 (1985) didn't use them, so that gives a time period. As far as

One lecture from 2004 discusses the buffered clock tree in the Alpha 21064 (1992), while the 386 (1985) didn't use them, so that gives a time period. As far as two phases, the lecture says that edge-triggered (rather than two-phase) is most popular (page 16). But I don't know about modern design. Link: https://web.stanford.edu/class/archive/ee/ee371/ee371.1066/lectures/Old/lect_08_2up.pdf https://web.stanford.edu/class/archive/ee/ee371/ee371.1066/l...