KarbosGuide.com. Module 2d.04

Chip sets for Intel's P6 processors

The contents:

  • An introduction to the early P6 chip sets
  • 82440LX
  • 82440BX
  • The Multi I/O controller
  • 82440EX for discount
  • VIA Apollo
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  • Chip sets for Pentium Pro

    Intel's Pentium Pro was an very early P6 processor, but with Pentium II this platform became very popular.

    The 6th. generation CPUs, Pentium Pro and Pentium II, have their own chip sets. Back in 1995 and 1996 this platform was not very interesting to most people, since the Pentium Pro was aimed at the server market. The situation changed in 1997 with the Pentium II.

    Let us review the chip sets in this family chronologically:


    This chip set came out in 1995, It is supporting quad CPU configurations. That is PCs with 4 Pentium Pros.

    82440FX - Natoma

    This was for a long time Intel's most widely used chip set for 6th. generation CPUs.

    This chip set can handle 2 CPUs on the same motherboard. 440FX consists of four controllers. As for features, it is like the 82430HX set. Common for these chip sets is the 82371SB PCI-ISA accelerator, which provides good performance on the I/O buses.

    This chip set is good and fast. However, it supports neither SDRAM, Ultra DMA, or AGP. These features are found in the following chip set 82440LX.


    440LX is from August 1997. The news were USB, SD-RAM and Ultra DMA. Thus, this chip set is equivalent to 430TX.

    Another new feature was the AGP, which is a high speed graphics bus (Accelerated Graphics Port). The AGP-bus runs at 66 MHz - twice the speed of the PCI bus. This gives new power to the video system, and it frees the PCI bus from all the heavy video work. The AGP adapters also extend their memory using parts of the motherboard RAM as a bit map cache.

    This model illustrates the architecture:


    The 440BX chip set was released on April the 15th 1998. In time it became the most popular for Pentium IIs as well as Celerons and Pentium IIIs.

    The chip set contains the 82443BX Host Bridge (north bridge) and the 82371EB PIIX4E (south bridge):

    The system bus speed was increased to 100 MHz. This chip was designed for the Pentium II and III chips, which ran at 350, 400, 450, 500, etc. MHz . The 100 MHz system bus speed is multiplied with clock factors from 3.5 up to 8.

    The BX chip set controls up to 512 MB of memory (100 MHz SDRAM).

    A motherboard like Asus P2B can clock the 100 MHz system bus from 2 to 8 times - theoretically allowing the CPU to work with a clock frequency of up to 800 MHz!

    Other motherboards (i.e. EPoX P2-133A) allow the system bus to reach 133 MHz. Abit's BX6 ver. 2.0 even goes up to 153 MHz using the BX chip set. In that case the you need cooling of the north bridge controller unit.

    Here you see the north bridge controller situated very close to the slot 1 connection. It is hiding under the green cooling element in the center of the picture:

    The chip set promised better bandwidth for PCI and AGP using a Quad Port technology, which is not explained anywhere. It was expected that the BX chip set should support the IEEE1394 bus (FireWire) but it does not.

    The Multi I/O controller

    On all modern P6 based motherboards you find a so-called multi I/O controller. It is a chip which traditionally connects to the ISA bus. It controls ports like COM, LPT, KBD etc.

    On many BX based motherboards you find the Winbond 83977 controller:


    The EX chip set is a discount version of the LX set. The chip set only supports DIMM sockets with up to only 256 MB RAM and just three PCI slots. To be used with the inexpensive Celeron cartridges.

  • 82443EX PCI AGP Controller (PAC)
  • 82371AB PCI-TO-ISA/IDE Xcelerator (PIIX4)

    VIA Apollo Pro

    Via also produces chip sets for Intel's Slot 1 cartridges (Celeron, Pentium II, and Pentium III) and for socket 370. They have become the second largest producer of chip sets, and their products are used by major vendors like Compaq and Dell.

    The Apollo+ set is much similar to Intel's BX chip set. It consists of two chips of similar size. It takes up to 1 GB RAM where BX only handles 512 MB.

    Newer versions of the chip set support PC133 SDRAM and later in 2001 support for PC266 DDR RAM is expected.

    The following is taken from VIA's own material.

    Apollo Pro+

    The VIA Apollo Pro Plus consists of two devices. You see the north bridge to the left:

    The VT82C693 combines with the new VT82C596A, a BGA-packaged southbridge with a full set of mobile power management features for high performance, power-conscious desktop and mobile designs. VT82C693 North Bridge

  • Supports all Slot 1 (Intel Pentium II) and Socket 370 (Intel Celeron ) processors
  • AGP / PCI / ISA Mobile and Deep Green PC Ready
  • 66 / 100 MHz CPU external bus speed (internal 450MHz and above)
  • AGP v1.0 and PCI 2.1 compliant. Supports SideBand Addressing (SBA) mode. Concurrent CPU and AGP access
  • Supports FP, EDO, and SDRAM
  • Different DRAM types may be used in mixed combinations
  • Supports 8 banks up to 1GB DRAM
  • 5-2-2-2-2-2-2-2 back-to-back accesses for EDO DRAM
  • 6-1-1-1-2-1-1-1 back-to-back accesses for SDRAM
  • Pipelined transfers up to 533 MB/sec
  • Supports up to five PCI masters
  • Windows TM 95 OSR-2 VXD and integrated Windows TM 98 / NT5 miniport driver support VT82C596A South Bridge

  • PC98-Compatible Mobile Power Management: Supports both ACPI (Advanced Configuration and Power Interface) and legacy (APM) power management
  • Sideband signal support for PC/PCI and serial interrupt for docking and non-docking applications
  • Supports external APIC interface for symmetrical multiprocessor configurations
  • USB v.1.0 and Intel Universal HCI v.1.1 compatible Microsoft Windows TM 95 and plug and play BIOS compliant
  • Supports ATAPI compliant devices including DVD devices
  • Integrated USB Controller, UltraDMA-33 master mode and EIDE controller

    VIA and S3

    A product produced by S3 VIA, code named SavageNB, will combine the best of S3's Savage4 graphics engine with VIA's Apollo Pro core logic design.

    By integrating the two key technologies, S3 and VIA effectively combine three components (North Bridge, the graphics controller and frame buffer) into a single chip configuration.

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    Read about RAM in module 2e

    Read about the Pentium in module 3c

    Read about the Pentium II's etc. in module 3e

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