Supermicro P4SGA+ User Manual download pdf (Page 19)

Chapter 1: Introduction

1-13

1-2 Chipset Overview

Intel’s 845G chipset (P4SGA) is made up of two primary components: the

Graphics Memory Controller Hub (GMCH) and the I/O Controller Hub (ICH4).

The 845GL (P4SGL) and 845GE (P4SGR/P4SGE) chipsets also include these

components, however the 845GL provides no AGP support and only a 400

MHz system bus speed and the 845GE supports faster memory.

Graphics Memory Controller Hub (GMCH)

The GMCH includes the host (CPU) interface, memory interface, ICH4 inter-

face and 4xAGP interface for the 845G/GL/GE chipset. It contains ad-

vanced power management logic and supports a single channel of DDR

SDRAM. The AGP 2.0 interface supports 4x data transfers and operates at

a peak bandwidth of 1.6 GB/s.

An external graphics accelerator card is not required due to the integrated

graphics in the 845G/GL/GE chipset. (If the system BIOS detects an exter-

nal AGP device, it will disable the integrated graphics.) The integrated

graphics controller delivers 3D, 2D and video capabilities, including video

conferencing applications. The controller does not utlilize local memory, but

accesses graphics data located in system memory at speeds matching that

of the SDRAM installed. It also includes a cache controller to avoid frequent

memory fetches of recently accessed texture data.

I/O Controller Hub (ICH4)

The ICH4 is a fourth-generation I/O Controller Hub subsystem that integrates

many of the input/output functions of the chipset, including a two-channel

ATA100 Bus Master IDE controller. The ICH4 also interfaces with the PCI

cards, the AC'97 Audio CODEC and the various communications ports.

Nearly all communications between the GMCH and the ICH4 takes place

over the hub Interface, which is a 66 MHz/266 MB/s bus.

Recovery from AC Power Loss

BIOS provides a setting for you to determine how the system will respond

when AC power is lost and then restored to the system. You can choose

for the system to remain powered off (in which case you must hit the

power switch to turn it back on) or for it to automatically return to a power

on state. See the Power Lost Control setting in the BIOS chapter of this

manual to change this setting. The default setting is Always OFF.

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 92 93

No comments

Supermicro P4SGA+ User Manual Page 19