Pentium 4 (P4) is the Intel processor (codenamed Willamette) that was released in November 2000. The P4 processor has a viable clock speed that now exceeds 2 gigahertz (GHz) - as compared to the 1 GHz of the Pentium 3.
P4 had the first totally new chip architecture since the 1995 Pentium Pro. The major difference involved structural changes that affected the way processing takes place within the chip, something Intel calls NetBurst microarchitecture. Aspects of the changes include: a 20-stage pipeline, which boosts performance by increasing processor frequency; a rapid-execution engine, which doubles the core frequency and reduces latency by enabling each instruction to be executed in a half (rather than a whole) clock cycle; a 400 MHz system bus, which enables transfer rates of 3.2 gigabytes per second (GBps); an execution trace cache, which optimizes cache memory efficiency and reduces latency by storing decoded sequences of micro-operations; and improved floating point and multimedia unit and advanced dynamic execution, all of which enable faster processing for especially demanding applications, such as digital video, voice recognition, and online gaming.