English
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GermanCurrent technologies in the architecture of motherboards on i440BX
(Continuation)
Evgenie Rudometov, Victor Rudometov.
authors@rudometov.com
Article is grounded on substances of books "Arrangement of the multimedia computer" and "Motherboards and chip sets"
The chip set i440ВX (i440ВX AGPset) is oriented for operation in systems on the basis of processors of the sixth generation which processors of Intel Celeron concern, Pentium II and Pentium IIIс by Slot 1 plugs and Socket 370. In the chip set architecture support AGP, QPA (Quad Port Acceleration) is carried out. Power management on the basis of ACPI is realised. It is effective in tasks of multimedia. It is calculated for memory sizes SDRAM to 1 Gbytes and frequency 60, 66 and 100 MHz of the bus of processor FSB (64 bits Host Bus GTL +). Can use in dual-processor patterns. Supports SMP protocol (Supports full symmetric Multiprocessor Protocol) for systems with number of processors to 2, buffering, hardware of dynamic fulfilment of commands and a pipeline way of data transfer, resource I/O APIC, AGP 1X/2X videoadapter modes, 2 channels IDE with UltraDMA/33 etc .
The chip set i440BX consists of two chips: 82443BX and 82371AV/EB, fulfilling functions accordingly North Bridge and South Bridge. A chip 82443BX — Host Bridge/Controller PCI AGP (PAC). A chip 82371AV/EB — PCI-TO ISA/IDE Xcelerator (PIIX4/PIIX4Е).
Structure of the computer with a chip set i440BX AGPset
The chip set i440BX is a synchronous chip set. It means, that frequency of the bus of memory is always equal to frequency of the bus of processor FSB (Host Bus). Some experts consider, that it is one of secrets of its high efficiency as at existing algorithms of synchronisation of processes of an information transfer the main subsystems difficultly in asynchronous or pseudo-synchronous modes to realise their optimal operation causing high efficiency of all system of the computer.
In spite of the fact that the chip set is calculated for frequency of 100 MHz FSB, it as practice shows, perfectly works at the raised frequencies, for example, at 133 MHz and even above. However there are also some problems by chip set operation in similar frequency modes. The matter is that the realised dividers and multipliers frequency the buses of processor FSB setting values of frequencies for buses AGP and PCI, often limit growth FSB. It is linked by that at frequency of 133 MHz FSB the computer videoadapter is forced to work at clock rate of 89 MHz. So high value clock frequency, considerably, exceeding standard 66 MHz for bus AGP, sometimes negatively affects stability of operation of the videoadapter, and, eventually, and all system of the computer. The similar problems linked to operation of hardware at raised frequencies, can be observed and with the arrangements which have been hooked up to bus PCI. In spite of the fact that in a chip set for a divider setting frequency value on bus PCI from frequency of bus FSB, except value "three" value "four" is supported, in the majority of motherboards this possibility remains non-realised. For this reason at frequency of bus FSB of 133 MHz and above quite often arrangements PCI are forced to work in astable modes. First of all it concerns the hard disks which usually are not guaranteeing a quiescent operation at frequencies above 40 MHz. However problems of creation of private modes of buses AGP and PCI are nonunique problems of the architecture of a specialised set i440BX.
To pass to razrelu Motherboards and chip sets