Motherboard Layout and Routing Guidelines

NLX Form Factor:

1.The NLX placement and layout below is recommended for a single (UP) Intel® Pentium® II processor / Intel® 440GX AGPset system design.

2.The example placement below shows one Slot 1 connector, 4 DIMM sockets, and an AGP compliant device down.

3.For an NLX form factor design, the AGP compliant graphics device may readily be integrated on the motherboard (device down option).

4.The trace length limitation between critical connections will be addressed later in this document.

5.Figure 2-3is for reference only and the trade-off between the number of DIMM sockets, and other motherboard peripherals need to be evaluated for each design.

Figure 2-3. Example NLX Placement for a UP Intel® Pentium® II processor / Intel® 440GX Design

SDRAM DIMMs

 

 

 

 

 

 

CK100

AGP

 

 

 

 

 

SDRAM

 

 

 

 

Interface

 

AGP Interface

 

 

 

 

 

CKBF

82443GX

PCI Interface

 

 

 

Host Interface

 

 

 

 

Pentium ®

II Slot 1

 

Ports

 

 

 

 

I/O

 

 

 

 

PIIX4E

 

 

 

 

PCI0/ISA Riser

 

 

 

 

v003

2.2Board Description

For a single processor / Intel® 440GX AGPset motherboard design, a 4 layer stack-up arrangement is recommended. The stack up of the board is shown in Figure 2-4. The impedance of all the signal layers are to be between 50 and 80 ohms. Lower trace impedance will reduce signal edge rates, over & undershoot, and have less cross-talk than higher trace impedance. Higher trace impedance will increase edge rates and may slightly decrease signal flight times.

Intel®440GX AGPset Design Guide

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Intel 440GX manual Board Description, NLX Form Factor
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440GX specifications

The Intel 440GX chipset was launched in 1997 as part of Intel's series of chipsets known as the 440 family, and it served as a critical component for various Pentium II and Pentium III-based motherboard architectures. Specifically designed for the second generation of Intel’s processors, the 440GX delivered enhanced performance and supported a range of important technologies that defined PC architectures of its time.

One of the main features of the Intel 440GX was its support for a 100 MHz front-side bus (FSB), which significantly improved data transfer rates between the CPU and the memory subsystem. This advancement allowed the 440GX to accommodate both the original Pentium II processors as well as the later Pentium III chips, providing compatibility and flexibility for system builders and consumers alike.

The 440GX chipset included an integrated AGP (Accelerated Graphics Port) controller, which supported AGP 2x speeds. This enabled high-performance graphics cards to be utilized effectively, delivering many enhanced graphics capabilities for gaming and multimedia applications. The AGP interface was crucial at the time as it offered a dedicated pathway for graphics data, increasing bandwidth compared to traditional PCI slots.

In terms of memory support, the 440GX could address up to 512 MB of SDRAM, allowing systems built with this chipset to run comfortably with sufficient memory for the era’s demanding applications. The memory controller was capable of supporting both single and double-sided DIMMs, which provided versatility in memory configuration for system builders.

Another notable feature of the Intel 440GX was its support for multi-processor configurations through its Dual Processors support feature. This allowed enterprise and workstation computers to leverage the performance advantages of multiple CPUs, making the chipset suitable for business and professional environments where multitasking and high-performance computing were essential.

On the connectivity front, the chipset supported up to six PCI slots, enhancing peripheral device integration and expansion capabilities. It also included integrated IDE controllers, facilitating connections for hard drives and CD-ROM devices.

Overall, the Intel 440GX chipset represented a balanced combination of performance, flexibility, and technology advancements for its time. Its introduction helped establish a foundation for subsequent advancements in PC technology and set the stage for more powerful computing systems in the years to come.
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