Author: Nigel Woodford

Introduction

When the Pentium 4 was first released back in November 2000 it became Intel's fastest offering to date, although there were some specific circumstances under which it was outperformed by the Pentium 3 in some benchmarks. In addition, AMD’s Athlon became the choice for many computer enthusiasts during that time for many reasons. The Willamette core, the first variation of the Pentium 4 based on the .18 micron process, experienced issues due to the fact memory technology hadn't yet caught up with its enormous hunger for memory bandwith. In addition, the Pentium 4's lower Instructions Per Clock (IPC) meant that it needed higher clockspeeds than were available at the time to really hit it's stride. In addition to the Pentium 4's premium price, memory cost was also a problem. The fact that the 850, the first Pentium 4 Chipset, used Rambus memory didn’t help the situation. Rambus memory was very expensive at the time and had to be used in pairs. Eventually Intel started including Rambus in their retail Pentium 4 boxes. While this helped with availability, it unfortunately didn't help pricing too much.

Intel realized that supporting DRAM memory was the only way to get the Pentium 4 fully accepted into the mainstream, enthusiast, and low end markets. Their first DRAM chipset, the 845, only supported single data rate PC133. The 845 allowed use of the Pentium 4 with inexpensive memory. This helped the Pentium 4 saturate the low end market. Intel then released the 845D. This chipset was geared toward the mainstream/enthusiast market and supported DDR 266Mhz (133 X 2 double data rate). The 845D got things rolling for Intel. Coupled with the new Northwood core, the 845D was an amazing Overclocking platform. Users were easily Overclocking their Pentium 4 1.6A’s past the 2Ghz mark with stock cooling. The Northwood core put Intel back in the driver’s seat. The Pentium 4 was finally able to out perform AMD’s offerings. The Northwood core sporting 512K of L2 cache and the .13 micron process, became a major success for Intel and continues to lead the market in desktop performance.

The Pentium 4 architecture is very bandwidth hungry. The front side bus of the Willamette core was 400Mhz (100 X 4 Quad Data Rate). The Northwood core allowed Intel to increase the front side bus to 533Mhz (133 X 4 Quad Data Rate). One benefit that Rambus memory had was that it provided the Pentium 4 with exactly the amount of bandwidth it needed. DDR DRAM was unable to provide nearly as much bandwidth as Rambus. Once DDR DRAM began to increase in speed things started to change. The 845PE chipset from Intel and SIS 645/DX chipset allowed use of DDR 333MHz with Pentium 4’s. DDR 333Mhz provided 2.7GB/s of bandwidth, better performing than DDR 266Mhz, but still far from the 4.2GB/s the Pentium 4’s 533Mhz bus could utilize. Using DDR 400Mhz memory, it was very possible to Overclock your front side bus and achieve performance close to Rambus. Unfortunately, DDR 400Mhz was never “officially” supported in Pentium 4 chipsets until now.

Rumors have been going around for some time about Intel increasing the front side bus on their Pentium 4. We will be talking about a few things in this article including the new 800Mhz FSB, and, Supporting Chipsets.