Intel 875P and 865PEWhile not the first Dual Channel DDR chipset available for the Pentium 4, it certainly was the one that put the Pentium 4 on the map. The 875P chipset was designed by Intel using the experience gained from the E7205 chipset but with new additions. The 875P was Intels idea for a new chipset to support the 800MHz FSB Pentium 4 as well at Hyper-Threading technology and Dual DDR memory controller followed closely behind with the I865PE.
First off the 875P chipset was to come in two new parts, the i82875 Northbridge and i82801ER or EB Southbridge, depending on what variant the motherboard manufacturers want to put in place. The i82875 Northbridge is the heart of the operations designed with FSB support for either the 533 or 800MHz FSB CPU, 400MHz CPUs werent even considered for the high-end market. Along with the latest 800MHz FSB support, Hyper-Threading technology has been included for the use of Multi-Threading applications and operating systems to take full advantage of todays high demanding software applications.
Added to this is the latest support for DDR-400 memory. DDR-400 has been the product no one dare officially support. nVidia was for first to support DDR-400 on its nForce 2 platform, with Intel close behind. Not only has Intel finally pulled out DDR-400 as its memory of choice but it has now pushed on Dual Channel. Dual DDR was first pioneered by nVidia on its rather lacklustre nForce chipset, due to various issues with the chip; Dual DDR was looked on as a failure. The Intel Pentium 4 platform, however, was a prime candidate for Dual Channel DDR, due to the higher bandwidth requirements of the Netburst bus system.
For the 875P chipset, Intel wanted to squeeze every last drop of performance out of this chipset to not only take the enthusiast market but to push the 875P into the Entry level servers and Workstation PAT (or Performance Acceleration Technology) was introduced in order to combat some of the latency drawbacks that accompany 128bit DDR. PAT allows the 875P chipset to bypass some memory registers to allow the FSB to synchronise quicker with the memory to allow a greater memory response; we have only seen about 4% or 5% increase when using PAT.
The 865PE is Intels more mainstream chipset based directly on the core architecture of the 875P. The 865PE supports both the Dual Channel DDR 400 memory controller as well as the 800MHz FSB support. The major differences are the lack of both ECC memory support and PAT.
The two Northbridges are identically compatible with the Intel ICH5(R) Southbridges. Both Southbridges were designed especially for the latest technology such as eight High Speed USB 2.0 ports, AC97 version 2.2 supporting 5.1 audio channels as well as 6 PCI master slots. Serial ATA has been added to the Intel line. The ICH5 supports just plane serial ATA where the ICH5R allows for RAID functions such as RAID 0 and RAID1.
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