Recently Intel introduced their newest line of the Pentium 4 processors with the new Prescott core. In this paper I will discuss how the Pentium 4 processor works and the changes that have been made since its release, but mainly on the modifications in the newest Pentium 4's with the Prescott core. I will also briefly compare the performance levels of some of the different types of Pentium 4's.
The Pentium 4 line of processors encompasses a large range of clock speeds, from 1.7GHz up to 3.6GHz in the Prescott chip. Pentium 4's are all built with the same Netburst microarchitecture, but there are varieties of front side bus speeds, chip layout, and cores available. For example at 2.8GHz, one could choose from four different Pentium 4s: the 2.8GHz (a Northwood core with a 533MHz front-side bus), the 2.8C (Northwood again, but with an 800MHz bus), the 2.8A (Prescott with a 533MHz bus), or the 2.8E (Prescott with 800MHz bus). In all there are four types Pentium 4 versions that Intel has released each having slight improvements then the last.
The first Pentium 4 (Willamette) was introduced in November 2000 to replace its predecessor the Pentium 3. The Pentium 4 was the first to have a totally new chip architecture since the 1995 Pentium Pro. The biggest difference being Intel's introduction of the Netburst microarchitecture, which involved structural changes that affected how processing takes place within the chip. 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; 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.
In January 2002 Intel released a new version of the Pentium 4 with a new Northwood core. Northwood combined an increase in the secondary cache size from 256k to 512k with a transition to a new 0.13 micrometer (130 nm) process technology. By making the chip out of smaller transistors, it could run faster and yet consume less power. It also had a new socket (socket 478) which unfortunately made upgrades impossible. Bus speeds where also increased to 533MHz and then to 800MHz for processors running at 2.4GHz or more. Also hyper-threading which I will discuss later was introduced to some Pentiums 4's that ran at an 800MHz bus speed.
In September 2003, Intel announced it would release yet another version of the Pentium 4 which they called the Extreme Edition. The design was mostly identical to Pentium 4 (to the extent that it...