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Gigabyte GA-8I945G Pro architecture

Evgenie Rudometov

Developing the bar of the motherboards created on the basis of chipsets of the system logic of the bar of Intel 945, company Gigabyte has developed and has released model Gigabyte GA-8I945G Pro. In the architecture of this card a number of perspective firm and branch processing techniques is realised

The motherboards which are one of the major computer accessories, accumulate many branch processing techniques and standards in the architecture. Manufacturers permanently work over perfection of motherboards, expanding a band of their possibilities. As a result more and more the functions realised earlier by means of special, separate cards, become attributes of motherboards. It increases a functional saturation of motherboards, however it and raises a degree of responsibility of implementators and manufacturers of this sort of the major accessories.

Really, enough insignificant at first sight deformations of standards and processing techniques, and motherboard operation becomes labile. Moreover, even small errors of engineering do it completely disabled. For this reason it is expedient to use products from known manufacturers, whose level is checked up by time and experience and consequently does not call doubts.

Company Gigabyte entering into triple of the main manufacturers of motherboards in the world concerns their number of such manufacturers.

One of the models rather recently announced by company Gigabyte is card Gigabyte GA-8I945G Pro. This card supports processors of corporation of Intel, including topovye high-powered variants IntelPentium 4 and the newest two-nuclear models IntelPentium D in konstruktive LGA  775. Besides, two subsystems of hard disk drives with functions RAID, ports SerialATA 300 with capacity to 300 Mb per second, buses PCIExpress X16 and PCIExpress X1, gigabitnyj Ethernet, a multi-channel audiosystem of Intel High Definition Audio, etc. are realised two-channel dynamic storage DDRII SDRAM with DDRII 400/533/667 units  .

The newest chip set declared recently with the integrated graphics resources of Intel 945G became a basis of this card.

Intel chip set 945G motherboard Gigabyte GA-8I945G Pro

Fig. 1. Structure of the computer created on the basis of a chip set of Intel 945G

Intel chip set 945G (i945G) concerns bar I945 which has come in the stead I915. It is oriented to creation of high-powered desktop personal computers with the graphics resources built in a chip set as it earlier carried out I915G.

Supports systems with processors of Intel of Pentium 4 with processing technique Hyper-Threading, 90 nanometers created on processing technique , hooked up through LGA 775 plug and working with bus FSB of type QPB (Quad-Pumped Bus) which clock rate can make 133, 200, 266 MHz. It provides high-speed data transfer and addresses according to frequencies of 533/800/1066 MHz and 266/400/533 MHz.

The bus supports 32-bit addressing that provides to 4 Gbytes of dynamic storage.

Feature of chip set I945G is support of two-nuclear processors of Intel, that formally do not provide chip sets of previous I915 set.

Traditionally for chipsets of system logic chip set I945G consists of two components named Graphicsand Memory Controller Hub (GMCH) and I/O Controller Hub (ICH).

The base package of a chip set i945G consists of Intel chips 82945G Graphics and Memory Controller Hub (GMCH) and Intel 82801GB (ICH7). As the second chip the improved variant ICH7 presented by a chip of Intel 82801GR (ICH7R), possessing the expanded possibilities of operation with a disk subsystem of memory can use.

Chips GMCH and ICH are jointed by special Direct Media Interface (DMI local bus to a transfer rate to 2 Gbytes/with in each direction: a full duplex.

The GMCH component contains the controllers giving interfaces with high capacity in the structure. These controllers control the system bus with data transfer with frequency of 533/800/1066 MHz and two-channel dynamic storage. Besides, they will organise operation of the graphics resources presented by the built in graphics kernel of Intel Graphics Media Accelerator (GMA) 950 and graphic interface PCI Express x16 (to 8 Gbytes/c) for the external videoadapter, and also communication facilities with a chip of input/output ICH.

Built in Intel 82945G the controller of processor bus FSB of type QPB supports the bus with clock rate of 266/200/133 MHz that provides data transfer on frequencies of 1066/800/533 MHz.

Built in Intel chip 82945G the memory controller provides support of two-and one-channel functional modes of memory DDR/DDR2 SDRAM (Double Data Rate SDRAM — SDRAM with data transfer on lobbies and back edges of clock pulses of the bus of memory). Support only DDRII SDRAM (400/533/667) is provided. Unlike the previous set of I915 set the chip set i945G does not have possibility of a pattern of system with usage DDR SDRAM

Maximum size of dynamic storage — to 4 Gbytes. Two-channel memory DDR II SDRAM with frequency of 533 MHz has maximum capacity to 8,5 Gbytes/with, and with frequency of 667 MHz — to 10,7 Gbytes/with. Chip MCH supports different frequency functional modes for processor and memory buses.

The graphics kernel of Intel GMA 950 providing high efficiency of graphics operations and excellence of playback of videorecordings. Frequency of a kernel — 400 MHz, for the analogue display uses the built in 400 MHz 24-bit RAMDAC, modes to 2048 h 1536  75 Hz, for the digital display — two SDVO port are supported      , is supported DMI the interface etc .

Handle of computer peripheral devices is carried out by the second component of a chip set. Thus it is necessary to mark, that in a chip set i945G chip ICH of the seventh version is used. According to this fact it has received name ICH7 and is presented by Intel chip 82801GB. This chip enters into a base set of a chip set i945G.

The built in resources of a chip of handle of peripheral devices of a base set support: one channel IDE with support ATA 33/66/100 (to two arrangements IDE), four ports Serial ATA 300 (SATA II — to 300 Mb per second), eight ports USB 2.0, to four PCI Express x1, to six PCI (PCI Rev 2.3, 32 bits/33 of MHz), LPC (Low Pin Count), the controller of Intel High Definition Audio with support of three codecs, AC ’ 97 2.3 (to 8 channels), integrated controller LAN (10/100/1000 Mb/s Ethernet), SMBus, APIC, ACPI Rev.2.0, and also other resources and functions.

Except Intel 82801GB as it has been specified above, usage of the expanded version of hub ICH7 — ICH7R (support of functions RAID and to six PCI-E), presented by Intel chip 82801GR is possible .

It is necessary to add, that under the statement of the company of Intel and as shows testing, graphics kernel GMA 950 twice exceeds on productivity in tests 3DMark05 the previous integrated solution of Intel – GMA 900 (i915G). Support HDTV with the permission to 1080i is declared also.

Structure of package Gigabyte GA-8I945G Pro

Fig. 2. Structure of package Gigabyte GA-8I945G Pro

Into package structure standardly enter (a Fig. 2):

        the Packing box,

        Motherboard Gigabyte GA-8I945G Pro,

        the Cover plate of input/output corresponding to specification ATX 2.01, 

        the Compact disc with the software from Gigabyte,

        Cables Ultra DMA 66/100/, Serial ATA, Floppy,

        the Documentation.

The main technical parametres of motherboard Gigabyte GA-8I945G Pro

Fig. 3. Motherboard Gigabyte GA-8I945G Pro

Fig. 4. Motherboard Gigabyte GA-8I945G Pro plugs

The processor

        Support of processors of Intel of Pentium 4 and Intel of Pentium D in konstruktive LGA775 with the system bus of 1066/800/533 MHz and with processing technique Hyper-Threading (HT)

Chip set

        Northbridge: Intel 82945G (GMCH),

        Southbridge: Intel 82801GR (ICH7R).

Dynamic storage

        Four (1,8 plugs for dynamic storage DIMM,

        Support of two channels DDR II 667/533/400 (DDR 667 in a mode of 1066/800 MHz) SDRAM,

        Maximum size DDRII SDRAM — to 4 Gbytes.


        the Videoadapter in PCI slot Express x16.


        the Audiosubsystem on the basis of codec ALC882 CODEC,

        Support of 2/4/6/8 audiochannels.

Serial ATA

        Chip ICH7R,

        Four ports Serial ATA 300.


        Chip ICH7R,

        One port IDE (Ultra DMA 33/66/100).


        Chip ICH7R,

        Four ports Serial ATA for support RAID 0, RAID 1, RAID 0+1, RAID 5.


        Chip GigaRAID IT8212F,

        Two ports IDE (Ultra DMA 33/66/100/133),

        Support RAID 0, RAID 1, RAID 0+1, RAID JBOD.

USB 2.0

        Eight ports USB 2.0 (four – through a cable).


        Gigabitnaja (10/100/1000 Mbit/c) a network subsystem on base gigabitnogo network controller Broadcom 5789.

System BIOS

        Uses Award BIOS (under the licence).

Backboard ports

        keyboard and mouse Ports PS/2,

        One parallel port LPT,

        One port COAXIAL SPDIF Out,

        One port OPTICAL SPDIF Out,

        One port of VGA,

        Four ports USB 2,

        One port RJ45,

        Six plugs of audio (a 7.1-channel output, a linear input terminal, a microphone).

Input/output system

        the Controller of input/output IT8712.


        one PCI slot Express X16,

        two PCI slots Express X1,

        three PCI slots.

Form factor


        the Sizes of 305 mm h 220 mm.

Features of Gigabyte GA-8I945G Pro architecture

Motherboard Gigabyte GA-8I945G Pro (a Fig. 3, a Fig. 4) is created according to the existing requirements defined by high-frequency components and requirements energopitanija of two-nuclear processors.

It is necessary to mark, that motherboard Gigabyte GA-8I945G Pro is oriented as a basis of mass high-powered systems of wide application. The architecture provides support of the newest models of processors of Intel. These models concern topovye variants of Intel of Pentium 4, bar Extreme Edition processors, and also a new class of products — two-nuclear models. Expediently to use these processors working at high clock rates of the bus — 1066 and 800 MHz. However application and less efficient variants presented by processors of Intel Celeron, 533 MHz calculated for the bus is possible .

High efficiency of modern accessories is accompanied considerable teploobrazovaniem. It demands the adequate resources of cooling used in the architecture of the motherboard. For chips of a chip set they are presented by appropriate coolers (a Fig. 5). As is known, chip GMCH in the structure has rather powerful graphics kernel which operation is accompanied considerable teploobrazovaniem. Besides, and other components of this chip presented by controllers, responsible for link with the processor, dynamic storage subsystems, external videoadapters, link with chip ICH (in this case ICH7R), also select heat significant amount. Considering it, cooling copper heat sink GMCH is strengthened by the fan (a Fig. 5). As to the second chip of a chip set — ICH7R for maintenance of a necessary temperature mode implementators have counted sufficient usage of the small copper heat sink without additional resources of cooling.

Fig. 5. A part of Intel chip set 945G chips Graphics and Memory Controller Hub (GMCH) and I/O Controller Hub (ICH7) with cooling resources

Though the given heat sink has rather modest sizes, it successfully fulfils the functions in spite of the fact that into chip structure enter a considerable quantity of controllers of peripheral devices, including resources RAID.

Motherboard Gigabyte GA-8I945G Pro architecture is calculated for usage both one-channel, and two-channel patterns of a subsystem of dynamic storage with DDR units II SDRAM. Without limitations DDR units II 400 and 533 MHz can be applied . In modes with frequency of the processor bus of 800 and 1066 MHz probably usage of DDR units II 667. It is obvious, that two-channel patterns are preferable as provide reaching of a peak value of a pass-band for a dynamic storage subsystem, especially in case of application of DDR units II 667.

Usage of a two-channel pattern of dynamic storage with high-speed units is the important condition for productive work built in a chip set i945G video resources. For these resources videobuffers necessary for effective functioning represent a dynamic storage part on which capacity speed of operation of a video subsystem depends.

When productivity of the graphics resources built in a chip set probably usage of the separate videoadapter which is hooked up by means of bus PCI Express x16 does not suffice. Graphics solution PCI Express x16 provides speed to 4 Gbytes/with in each direction, that more than in three and a half time exceeds high-speed performance of the best external graphics adapters with interface AGP8X.

For handle of input\output devices the second component which is a part of the used chip set traditionally responds. As this component in Gigabyte GA-8I945G Pro Intel chip 82801GR (ICH7R), resulted on a Fig. 5 uses .

From features of the architecture it is necessary to mark an audiosubsystem realising processing technique of Intel High Definition Audio. It provides considerable improvement of playback of a multi-channel sound 48 kgts in comparison with traditional solutions AC ' 97. Support of new formats of house cinemas and support of simultaneous playback of several separate sound streams is Besides, carried out. As the codec chip Realtek ALC882 CODEC is used. It is realised eight audiochannels, providing rather excellence. So, for example, in a bar of 40 Hz – 15 kgts non-uniformity ACHH makes less than 0,2 db, a dynamic range — nearby 85 db, harmonious deformations — less than 0,01 %.

The network controller Gigabit Ethernet realised on a chip of controller Broadcom 5789 is built in the motherboard architecture, hooked up through bus PCI Express х1. The given integrated network tools allow to include easily the computer through built in RJ45 (LAN plug in local area network structure.

For the extension of the computer system created on the basis of motherboard Gigabyte GA-8I945G Pro, the appropriate slots presented by three traditional PCI plugs (to 133 Mb per second) and two PCI Express x1 (to 500 Mb per second) are  .

One more feature Gigabyte GA-8I945G Pro is the organisation of a disk subsystem of hard disk drives.

The motherboard architecture thanks to support of the component of chip set ICH7R incorporates four ports Serial ATA 300 (four arrangements) and one port Parallel ATA-100 (UltraDMA 100/66/33, two arrangements IDE).

Thanks to chip ICH7R which provides RAID with usage of disk drives Serial ATA, there is a possibility of implementation of functions RAID 0, RAID  1, RAID  0+1, RAID  5.

For the purpose of the extension of possibilities of the motherboard the additional chip which is ensuring functioning with an additional set of disk drives is integrated into its architecture — GigaRAID IT  8212F. This chip ensures functioning Parallel ATA IDE with support of UltraDMA 133/100/66 protocols, and also functions RAID 0, RAID 1, RAID 0+1, JBOD.

Fig. 6. The chips realising Dual BIOS

Considering possibilities of motherboard Gigabyte GA-8I945G Pro, it is necessary to mark, that this card supports variety of firm processing techniques.

Among them Dual BIOS — processing technique of the backup storage of program code BIOS in the second chip (a Fig. 6), that provides raised dependability at performance of operation of modification of a code, and also in case of virus attacks.

It is besides, supported CIA (CPU Intelligent Accelerator) 2 — dynamic change of frequency of the processor bus, and, therefore, and the processor depending on its current loading defined by character of executable tasks. Processing technique MIB is supported (Memory Intelligent Booster) 2, which allows to raise productivity (is declared — to 10 %) subsystems of dynamic storage at the expense of abbreviation of delays without stability lowering.

The developed system of dispersal (overclocking) is traditionally supported. It is helped by the firm utility EasyTune 5 working under Windows. It provides dispersal and monitoring of system parametres in real time.

Power supply of units of motherboard Gigabyte GA-8I945G Pro is carried out through system of impulse stabilising devices.

In the multi-channel impulse surge protector of the processor traditionally allocated round a processor socket, the considerable quantity of filtering capacitors is applied.

Except this converter, on the card there are additional converters of supply voltage PCI Express x16 and dynamic storage units.

In motherboard Gigabyte GA-8I945G Pro architecture possibilities of the hardware monitoring providing the control over supply voltages and operation of cooling fans are realised.

Stability and dependability

In the course of durable testing motherboard Gigabyte GA-8I945G Pro worked steadily as it usually and is characteristic for products of this manufacturer.

Motherboard Gigabyte GA-8I945G Pro can be recommended a wide range of users as a basis of the high-powered systems oriented to usage of high-powered variants of processors of Intel, including two-nuclear models, and calculated for usage both the graphics resources built in a chip set, and separate PCI Express x16 videoadapter.

Motherboard Gigabyte GA-8I945G Pro is given by company Marvel (, the official distributor of company Gigabyte

Article is published in log the Computer the Price (Computer Price).

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