> P4 was an engineering mistake. The story I've heard was that P4 was a management mistake. Some engineers claimed they surely understood that the limits exi

> P4 was an engineering mistake. The story I've heard was that P4 was a management mistake. Some engineers claimed they surely understood that the limits existed, but the management believed that the only thing that's sellable is a bigger number of GHz. So the engineers got the goal to make a processor architecture for 10 GHz, and apparently P4 was made for that (long pipelines) and it was known that on lower number of GHz the architecture performed worse. But 10 GHz was unachievable because physics can't be cheated (the chips would simply melt without some special cooling that was also not sellable), so P4 architecture was never driven with the clock speeds for which it was designed.