Because of its long-time integration of processor and chipset design, it's not surprising that Intel dominates the Pentium 4 chipset market as it has the markets for Pentium (P5) and Pentium II/III/Celeron (P6) markets in the past.

Although Intel has licensed Socket 423 (used by early Pentium 4 processors) and the current Socket 478 to rival chipset vendors such as SiS and ALi, Intel is still the leading developer of Pentium 4 chipsets.

Because the Pentium 4 and Celeron processors using Socket 423 and those made for Socket 478 are essentially the same processors with different cache designs and minor internal revisions, the same chipset can be used for both processors.

Intel 850 Family

The Intel 850 family contains two members, the original 850 and an enhanced version called the 850E. The 850 is the first chipset for the Intel Pentium 4 processor and thus is also the first chipset to support the NetBurst microarchitecture.

The 850 is designed for high-performance desktop computers and workstations and uses the same hub architecture and modular design as the rest of Intel's 8xx family of chipsets.

The 850 has two main components, down from three in earlier 800-series chipsets:

• 82850 Memory Controller Hub. Provides support for dual 400MHz RDRAM memory channels with a 3.2GBps bandwidth and a 100MHz system bus. The 82850 MCH also supports 1.5V AGP 4x video cards at a bandwidth exceeding 1GBps.

• 82801BA I/O Controller Hub 2. The ICH2 (an enhanced version of the 82801 used by other 800-series chipsets) supports 32-bit PCI rev. 2.2, dual UDMA 33/66/100 IDE host adapters, four USB ports, an integrated LAN controller, six-channel AC-97 audio/modem codec, FWH interface support, SMBus support, and Alert on LAN and Alert on LAN 2 support.

Optionally, the Intel 82562ET/82562EM Platform LAN communication chips can be added to the 850 chipset to provide support for 10BASE-T and Fast Ethernet networking, building on the LAN features in the 82801BA ICH2 chip.

The 850 chipset, similar to most recent Intel and non-Intel chipsets, also supports the CNR card for integrated audio, modem, and network capabilities.

The 850E is an enhanced version of the 850. Its 82850E MCH adds support for dual 533MHz Rambus RDRAM memory channels and support for PC1066 RIMM modules to the 850's standard features. It also uses the same ICH2 hub as the original 850.

Intel 845 Family

Unlike the 850 and 850E chipsets, the 845 family of chipsets is widely used by both Intel and third-party motherboard makers. If you purchased a Pentium 4 system from late 2001 through mid-2003, it probably uses some version of the 845 chipset.

The 845, code named Brookdale during its development, was the first Pentium 4 chipset from Intel to support low-cost SDRAM instead of expensive RDRAM. Subsequent variations support DDR SDRAM at speeds up to DDR333, ATA/100, and USB 2.0.

The 845-series chipsets include the following models:

• 845

• 845GL

• 845GV

• 845G

• 845GE

• 845E

• 845PE

All members of the 845 family use the same hub-based architecture developed for the 845 family, but they also have onboard audio and support the communications and networking riser (CNR) card for integrated modem and 10/100 Ethernet networking.

However, they differ in their support for different types and amounts of memory, integrated graphics, external AGP support, and which ICH chip they use.Although the original version of the 845 supported only PC133 SDRAM memory, the so-called 845D model (a designation used by review sites but not by Intel) also supports 200/266MHz DDR SDDRAM.

The Intel 845's 82845 MCH supports Socket 478–based Celeron or Pentium 4 processors and can support up to two DDR SDRAM modules or three standard SDRAM modules (depending on the motherboard). When DDR SDRAM is used, the 845 supports either 200MHz (PC2100) or 266MHz (PC2700) memory speeds, with an FSB speed of 400MHz.

The 845 also supports ECC error correction when parity-checked memory modules are used and offers an AGP 4x video slot, but it has no onboard video. The 845 uses the same ICH2 I/O controller hub chip (82801-BA) used by the Intel 850 and 850E chipsets in Rambus-based systems and the 815EP in low-cost SDRAM-based systems.

The ICH2 supports ATA/100 hard disk interfacing, basic AC'97 sound, and four USB 1.1 ports. All G-series 845 models feature Intel Extreme Graphics integrated video, which has faster core speeds and adds 3D performance to the bare-bones integrated video used by the 810 and 815 chipset families. Two chipsets—the 845G and 845GE—also offer support for AGP 4x video cards.

The 845E is an updated version of the current 845 model with ECC error correction and support for 533MHz FSB, whereas the 845PE supports the 533MHz FSB, DDR 266, and 333MHz memory, but it doesn't support ECC error correction. All models except the 845 (845D) use the enhanced ICH4 I/O Controller Hub 82801DB, which offers six USB 2.0 ports as well as integrated networking. Additionally, all models except the 845 and 845GL offer enhanced 20-bit audio.

Intel Extreme Graphics Architecture

845-series chipsets with integrated video (845G-series models) support Intel's new Extreme Graphics Architecture, which supports 3D graphics and features the following four technologies to improve 3D rendering speed and quality:

• Rapid Pixel and Texel Rendering Engine. Uses pipelines to overlap 2D and 3D operations, provides 8x data compression to improve the use of memory bandwidth, and features a multitier cache for 3D operations

• Zone Rendering. Reduces memory bandwidth requirements by dividing the frame buffer in to rectangular zones, sorting the triangles into memory by zone, and processing each zone to memory

• Dynamic Video Memory Technology. Manages memory sharing between the display, applications, and operating system depending on the memory requirements of the programs running

• Intelligent Memory Management. Improves memory addressing, display buffer implementation, and memory efficiency

Extreme Graphics Architecture improves 3D rendering compared to Intel's earlier integrated video chipsets (the 810 and 815-series chipsets, which have no 3D functions at all), but its performance and features still lag behind even current mid-range video chipsets from NVIDIA and ATI.

Extreme Graphics Architecture lacks hardware Transform and Lighting (T&L) features, a feature required by some of today's most popular games, and offers frame rates which, at best, are at about the level of the low-end NVIDIA GeForce 2 MX 200.

Thus, even though you can play an occasional game with the G-series systems with integrated video, if you want serious game play, you'll need one of the 845 models that supports AGP 4x graphics cards and DDR333 memory, such as the 845GE or 845PE.

Intel 865 Family

The Intel 865 chipset family, code named Springdale, was released in May 2003. As the name might suggest, the 865 series is designed to replace the 845 series with chipsets that feature dual-channel memory support, the new communications streaming architecture (CSA) that provides a dedicated connection for the integrated network controller, faster performance, and support for the latest technologies (including Gigabit Ethernet and Serial ATA).

The 865 family includes the 865P, 865PE, and 865G chipsets. The 865PE and 865G support single-channel or dual-channel DDR266, as well as dual-channel DDR333 and DDR400 SDRAM with FSB speeds up to 800MHz. Dual-channel memory provides a wider memory bandwidth for faster performance.

The 845P model supports DDR266/333 and FSB speeds up to 533MHz. All models support AGP 8x, and the G model includes Intel Extreme Graphics 2—a faster version of the integrated graphics technology found in G-series versions of the 845 chipset family.

All members of the 865 family use the new ICH5 I/O controller hub. A faster hub architecture called Hub Link 1.5 with 266MBps bandwidth connects the MCH/GMCH and ICH together.

ICH5 and ICH5R

ICH5 and ICH5R (Raid) are the latest generation of Intel's I/O controller hub, which is the equivalent of the South Bridge in Intel's hub-based architecture introduced with the 800 series of chipsets.

ICH5 and ICH5R feature four USB 2.0 controllers with eight external ports, two ATA/100 ports, and two Serial ATA/150 ports. ICH5R models add support only for RAID 0 (striping) on the SATA ports. ICH5/ICH5R also support the PCI 2.3 bus and include an integrated 10/100 Ethernet LAN controller.

Intel 875P

The Intel 875P chipset, code named Canterwood during its development, was introduced in April 2003. The 875P chipset supports Intel's HT Technology (hyper-threading), so it fully supports 3.06GHz and faster Pentium 4s, including the newer Prescott (90nm) core versions.

For faster memory access, the 875P supports four standard or ECC memory modules (up to 4GB total) using DDR333 or DDR400 memory in a dual-channel mode, and it offers a new Turbo mode that uses a faster path between DDR400 memory and the MCH to boost enhanced performance.

Because multiple memory modules aren't always the same size or type, the 875P also features a new dynamic mode that optimizes system memory when different types or sizes of memory are used at the same time. The 875P also includes both Serial ATA and RAID support and uses the same ICH5 I/O controller hub used by the 865 series.