the Pentium 4 was introduced at the end of 2000 with 1.4 and 1.5 GHz clock rates. Speed later reached 3.8 GHz. Pentium 4 chips were first built with 180nm process technology and subsequently ...
The first CPU to reach a clock speed of 4 GHz was the Pentium 4 570 released in November 2004 as part of Intel's NetBurst microarchitecture, but this milestone wasn't achieved out of the box.