P4 was also, initially, process-driven. The fab side of Intel had a huge priority in setting early architectural themes. And some of the CMOs flows in lab, in

P4 was also, initially, process-driven. The fab side of Intel had a huge priority in setting early architectural themes. And some of the CMOs flows in lab, in mid 90s, were showing huge speed scaling, but they had very restrictive design rules and cell libraries. But with the payout of extreme GHz scaling. From that point of view, the P4 made sense; a narrow architecture with very deep pipelines. Where each stage used the tiny datapaths between latches/registers those libraries supported. Netburst makes sense in terms of dealing with extremely deep out of order pipelines. However, those processes never met the scaling roadmaps. While the power consumption scaled horribly, and things like thermal, leakage and variability started to become first order limiters.