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IС7-G architecture from Abit

Evgenie Rudometov, Victor Rudometov.

Abit corporation releases motherboard Abit IC7-G. The high-powered chip set of Intel 875P became a basis of this card. The given card in which the big number of firm processing techniques is realised, is oriented to creation of the high-powered computer systems which basis is made by processors of NetBurst architecture with processing technique Hyper-Threading.


Forming structure of the future computer, it is necessary to give especially steadfast attention to a motherboard choice. Considering a variety of the presented models, occasionally this choice to make uneasy.

Tens large and small manufacturers persistently recommend to potential users the products. However was usefully to remind, that offered models of motherboards differ not only the price and packing, but also functionality, parametres of dependability and stability of operation. Thus the given parametres substantially depend on a choice of chips and quality of manufacture of cards corporations-manufacturers.

Once again it is necessary to underline, that the architecture of modern motherboards is grounded on application of the newest electron technologies accumulating experience of development of all branch. Implementation of these processing techniques is carried out mainly through used chips, design and features of production of these cards. From these components, their parametres, and also from quality of manufacture of cards functionality and operation of the future computers depend, eventually.

Many computer corporations which number makes some tens are engaged in development and release of motherboards. Some of these corporations thanks to production are well familiar not only to experts, but also ordinary users. One of such manufacturers is well-known Abit corporation. This corporation releases a wide spectrum of the products oriented to modern high-powered processors.

As an example of the cards developed under processors of Intel of Pentium 4 and Intel Celeron of NetBurst architecture, created and released by experts of the corporation of Intel, it is possible to result motherboard ABIT IC7-G. This card is among rather new models of the motherboards developed on the basis of the most powerful modern chip set of Intel 875P, intended for the mass products used at offices and at home.

Motherboard Abit IC7-G is oriented to creation of powerful workstations and high-powered desktop personal computers. As well as all products on the basis of Intel chip set 875P, this card allows to realise in a maximum degree all advantages of the architecture of processors of Intel of Pentium 4 with processing technique Hyper-Threading, supported by the given chip set.

Intel chip set 875P motherboard Abit IC7-G

Intel chip set 875P (i875P, known as Canterwood) is oriented to the architecture of workstations and high-powered desktop PCs. Supports systems with processors of Intel of Pentium 4 with processing technique Hyper-Threading, 0,13 microns created on processing technique . The given processors are hooked up through Socket 478 plug and work with bus FSB of type QPB (Quad-Pumped Bus) which clock rate for the given chip set can make 133 or 200 MHz. However usage of the models calculated and on frequency of the bus of 100 MHz is possible .

The chip set i875P consists of two components — Memory Controller Hub (MCH) and I/O Controller Hub (ICH), jointed by bus Hub Link (256 Mb per second).

MCH component is presented by Intel chip 82875P, containing resources of interfaces of operation with the processor, AGP videoadapter, dynamic storage units, and also with chip I/O Controller Hub.

Built in Intel chip 82875P the memory controller provides support: two-and one-channel functional modes of memory DDR SDRAM (Double Data Rate SDRAM — SDRAM with data transfer on lobbies and back edges of clock pulses of the bus of memory), DDR400/333/266, a maximum memory size — to 4 Gbytes, chips 128, 256, 512 Mbit DDR SDRAM, units both with ECC, and without ECC. In patterns with support ECC in a two-channel mode the bus of 144 bits, without support ECC — 128 bits uses   .

Chip MCH supports different frequency functional modes for processor and memory buses.

For a synchronous functional mode of memory DDR400 and frequency of the bus of 800 MHz probably usage of the mode providing raised productivity of a subsystem of memory, — processing techniques of Intel PAT (Performance Acceleration Technology). In this mode the delays linked to synchronisation are minimised.

The built in controller of a drawing supports one arrangement 0,8/1,5 In AGP 3.0, working in modes AGP 8х/4x.

In the architecture of a chip of Intel 82875P the special interface is provided, allowing to realise Gigabit Ethernet. Carrying over of these resources from ICH in MCH speaks insufficient capacity of the local bus jointing hubs MCH and ICH.

Handle of computer peripheral devices is carried out by Intel chip 82801ЕB — ICH the fifth version which are a part of a base package of a chip set i875P.

The built in resources of a chip of handle of peripheral devices of a base set support: two channels IDE with support ATA 33/66/100 (to four arrangements IDE), two ports Serial ATA 150, eight ports USB 2.0, six PCI (32 bits/33 of MHz), LPC (Low Pin Count), AC ' 97 with support of three codecs of the audiochannels, integrated controller Ethernet 10/100 Base-TX, SMBas, ACPI 2.0, and also other resources and functions.

Except Intel 82801ЕB, usage of the expanded version of hub ICH5 — ICH5R is possible . This expanded variant is presented by Intel chip 82801ЕR which differs from the predecessor function RAID of level 0.


The main technical parametres of motherboard Abit IC7-G


Fig. 1. Motherboard ABIT IC7-G developed and released by Abit corporation


Fig. 2. Motherboard ABIT IC7-G plugs


The processor

  • Support of processors of Intel of Pentium 4 with processing technique Hyper-Threading with the bus 800, 533, 400 MHz in 478-contact tank mPGA.

Chip set

  • Intel 82875P (MCH) and Intel 82801ER (ICH5R);
  • Two channels DDR400 with ECC and PAT;
  • USB 2.0;
  • Two ports Serial ATA 150 c support RAID 0;
  • Ultra ATA 100/66/33 protocol;
  • Five PCI plugs.

Dynamic storage

  • Four plugs (184 contact electrodes) for dynamic storage DIMM, DDR 400, DDR333, DDR266 (2,5 In, 128/256/512/1024 Mbit, unbuffered), is supported mode ECC, maximum size — to 4 Gbytes;
  • Support of one or two channels of dynamic storage.


  • One general-purpose AGP plug (Accelerated Graphics Port) with 1,5 or 0,8 In AGP 3.0, providing support AGP Pro 50 with modes AGP 8X/4X.


  • Audiosubsystem on the basis of 6-channel codec RealTeak ALC650 CODEC;
  • 24 bits S/PDIF Input/Output.


  • The integrated network controller of Intel CSA Gigabit (RJ45).


  • Two channels (two connectors) Ultra DMA 100/66/33;


Dual Serial ATA RAID

  • Two channels (two connectors) Serial ATA 150 with RAID 0 through ICH5R;
  • Two channels (two connectors) Serial ATA 150 with RAID 0/1 through Silicon Image PCI.

USB 2.0

  • Eight USB 2.0 with support of a transfer rate to 480 Mbit/with.


  • IEEE1394 c support of a transfer rate 400/200/100.

System BIOS

  • SoftMenu for processor parametre setup;
  • Plug-and-Play (PNP);
  • Advanced Configuration Power Interface (ACPI);
  • Desktop Management Interface (DMI);
  • Write-Protect Anti-Virus function.

Internal I/O plugs

  • One AGP slot;
  • Five PCI slots.
  • One Floppy port (supports arrangements in size to 2,88 Mb);
  • Two Ultra ATA 100/66/33;
  • Four Serial ATA 150;
  • Two USB 2.0;
  • Two IEEE1394a;
  • CD-IN, AUX-IN;
  • IrDA.

External I/O plugs

  • PS/2 The keyboard and PS/2 the mouse;
  • One parallel port (Parallel), a serial port (COM);
  • S/PDIF In;
  • S/PDIF Out;
  • AUDIO1 (Rear-Left / Rear-Right, Center/Subwoofer);
  • AUDIO2 (Mic-In, Line-In, Front-Left/Front-Right);
  • Two USB 2.0, one IEEE1394;
  • Two USB 2.0, one RJ-45 LAN.

Additional possibilities

  • Monitoring of powers, temperatures and operation of fans;
  • Support Wake Up by LAN, Modem Ring RTC Alarm, inclusion from the keyboard and the mouse;
  • Support STR (Suspend to RAM).

Form factor

  • ATX.


Structure of a package of motherboard Abit IC7-G

Into package structure enter:

  • Box;
  • Motherboard Abit IC7-G;
  • Compact disc with drivers and utilities
  • Diskette with drivers Serial ATA;
  • The user manual in English with short descriptions in different languages, including Russian;
  • Cable (round) for hooking up of arrangements ATA 100/66;
  • Cable (round) for hooking up of the flexible drive;
  • Two cables for arrangements Serial ATA;
  • Two adapters of power supply for arrangements Serial ATA;
  • Adapter Serillel2;
  • The cover plate of input/output corresponding to specification ATX;
  • breket with two USB 2.0 plugs and with two IEEE1394 plugs.


Fig. 3. A package of cables of motherboard ABIT IC7-G


Features of the architecture and design of motherboard Abit IC7-G

Fig. 4. Design of motherboard ABIT IC7-G


The design of motherboard Abit IC7-G developed and released by Abit corporation, as a whole corresponds to the referens-design of similar products created and recommended by corporations, releasing sets of system logic.

As card Abit IC7-G is oriented to application in high-powered systems, therefore in the systems created on the basis of the given card, usage of processors of Intel of Pentium 4 with processing technique Hyper-Threading and the bus of 800 MHz is recommended  . It provides reaching of a maximum level of productivity. However usage and less efficient models is possible. It can be, for example, the processors calculated for the bus of 533 MHz and even of 400 MHz. Thus together with motherboard Abit IC7-G created on the basis of a chip set i875P, application of models and without support of processing technique Hyper-Threading is possible. However together with this card can be maintained and models of processors Celeron though, it is necessary to recognise, that it does not provide the high levels of the productivity accessible to more efficient variants of processors and the given motherboard.

The functional mode of memory modules DDR SDRAM can be as one-channel (3,2 Gbytes/c), and two-channel (6,4 Gbytes/c). Thus first two DIMM slots of motherboard Abit IC7-G concern the first channel built in a chip set i875P the memory controller, last two — to the second channel.

It is necessary to mark, that the two-channel mode allows to receive completely depthbalanced system. It is provided in the event that pass-bands of the processor bus and the memory bus coincide and make equal values — 6,4 Gbytes/with. Thus operation of memory modules DDR SDRAM can be or synchronous — clock rate coincides with frequency FSB, or asynchronous — clock rate differs from frequency FSB. It is set in BIOS Setup — SDRAM Frequency.

The built in resources of the motherboard allow to change a standard set tajmingov ("SDRAM Cas Latency" and "Precharge to Active" (Trp), "Active to precharge" (Tras) and "Active to CMD" (Trcd), etc.).

In case of a synchronous mode for frequency of the bus of 800 MHz and memory modules DDR400 usage of the mode providing raised productivity of a subsystem of memory is possible. This processing technique realised in all products, created on a basis i875P, carries the name “PAT” (Performance Acceleration Technology). The idea laying in its basis, consists in an expedition of passing of data through MCH at the expense of refusal superfluous in this case synchronisations. Thus will not be involved superfluous sinhronizatsionnye bufery in a chip set, and data are handled directly. By estimations of experts of Intel, the reached scoring makes 2-5 %.

The design of the motherboard has a number of features.

First of all, it is necessary to mark processor Socket 478 plug. Unlike the previous models, for example, popular model Abit IT7-MAX2, processor Abit IC7-G plug will turn on 90 degrees (counter-clockwise). Its offset deep into the motherboard allows to use heat sinks of the big size.


Fig. 5. The plug of processor Socket 478


One more feature of design Abit IC7-G are resources of cooling of chip MCH. In spite of the fact that the referens-design of the motherboard from Intel corporation provides passive cooling of the given chip, engineers Abit used traditional solution for the products — rather small heat sink supplied with the fan. It on a plan of implementators raises stability of operation of the card, especially in modes of the dispersal advocated by Abit corporation in the products.


Fig. 6. Chip MCH of a chip set i875P with cooling resources


The second chip of a chip set i875P — ICH5R, responsible for input/output, thanks to insignificant teploobrazovaniju in cooling resources does not require, as has found reflexion in design Abit IC7-G.


Fig. 7. Chips ICH5R (Intel 82801ЕR, responsible for input/output) a chip set i875P, IEEE1394, Serial ATA and FWH (BIOS)


In the motherboard architecture, except chips of Intel and Abit, units of such corporations, as Abit, RealTek, Avance Logic (division RealTek), Texas Instruments and others are used.

One more important feature of the architecture and design of motherboard Abit IC7-G is usage of the resources providing implementation of interface Serial ATA 150. In the card 4 channels Serial ATA are provided. Moreover, possibilities RAID are realised. Thus two channels are provided by the built in resources of chip ICH5R, and other two channels Serial ATA — chip Sil3112A.

Support of interface IEEE1394 known as Firewire, is carried out by means of chip Texas Instruments TSB43AB23.

audiosredsta are provided by chip ALC650. The given integrated controller provides a six-channel sound

The special adapter besides, a part of a package provides compatibility of perspective interface Serial ATA with becoming outdated ATA (IDE). This adapter is named by Abit corporation as Serillel. These adapters provide hooking up through appropriate cables to Serial ATA plugs of arrangements ATA extended now. ROM/R/RW CD, similar CDs concern the given arrangements drives DVD, etc., as is known, widespread HDD .

As a part of motherboard Abit IC7-G package adapter Serillel2 created on the basis of chip Image Sil3611 is offered.


Fig. 7. Adapter Serillel2 providing hooking up to Serial ATA plugs of arrangements ATA


In the motherboard architecture the integrated network controller of Intel CSA Gigabit (Intel 82547 Gigabit Ethernet), providing a transfer rate 1 Gbit/with. The given built in network tools allow to include easily the computer through built in RJ-45 plug in structure of a high-speed local area network.

As well as all motherboards of the given corporation, Abit IC7-G supports dispersal modes.

For enthusiasts of dispersal there is a possibility of installation of the forced functional modes of the processor. It is carried out by frequency rise (change of frequency of bus FSB in a band from 100 to 412 MHz with step 1 MHz) processor bus FSB (overclocking) and memory buses, and also a choice of best values of parametres of operation of DDR SDRAM units.

The built in resources of motherboard Abit IC7-G allow to change power of the processor (Vcore) in a band from 1.525 In to 1.9 In with step 0.025 Century

In addition to it there is a possibility of change of level of the power submitted on memory modules (Vmem). The band of change of the given parametre makes from 2.5 In to 2.8 Century

Besides, it is possible to change the power submitted on the videoadapter. A change band — from 1.5 In till 1.65 In with step 0.05 Century

Rise of dependability and stability of operation is promoted by implementation of the hardware monitoring providing the control over supply voltages and operation of cooling fans. This possibility simplifies the control in case of usage of modes of dispersal.

The additional control devices facilitating performance of assemblage and reconfiguration of hardware of the computer are provided also. So, for example, when on the card the power moves, the green light-emitting diode on the motherboard lights up. After start the red light-emitting diode lights up. Check light-emitting diodes are allocated about chip FWH.

Card Abit IC7-G resources realise function Abit FanEQ which allows to regulate speed of rotation of a processor cooler depending on temperature. It provides essential lowering of noise level.

One more feature of Abit IC7-G architecture — usage of a fourline variant of the converter of power (VRM), characteristic for Abit corporation motherboards. Usually VRM it is allocated between the processor and input/output plugs. However apparently on the resulted fragment (a Fig. 8), layout VRM on motherboard Abit IC7-G is nonconventional.


Fig. 9. Fourline VRM motherboard Abit IC7-G


Estimating operation parametres of the described motherboard, it is necessary to mark, that at performance of numerous, durable tests card Abit IC7-G worked steadily, providing high efficiency of the computer, however it is a subject of one of following articles.


Motherboard ABIT IC7-G is given by the Moscow representation of Abit corporation.

It is published in log "the Computer the Price"

To pass to razrelu Motherboards and chip sets