Dealer Focus: Motherboards
After a cautious start, the Pentium Pro is gradually increasing its market share as more and more software that can use 32-bit architecture becomes available. We take a look at 10 motherboards that can form the basis of a Pentium Pro system
Although the opposite may appear to be true, there is little difference between a motherboard for a Pentium and one for a Pentium Pro. The Pentium Pro motherboards are usually slightly larger, however, because of the size of the socket that houses the microprocessor.
A large number of the boards analysed use the ATX format, which provides a flexible way of distributing the circuits and components in a printed circuit. One noticeable difference is the absence of secondary cache sockets ? although this should come as no surprise, because the Pentium Pro incorporates this feature in the chip itself.
On the other hand, there are four or more sockets for 72-pin memory modules, but boards capable of accepting Dimms are rare. The microprocessor socket is now called socket eight, which also refers to Overdrive processors where they exist for the Pentium Pros.
Unlike Pentium boards, where jumpers are usually required to configure the operating voltage, a voltage control module is normally used on Pentium Pro boards. It is inserted into a special socket base which supplies the required voltage. A few boards, however, require an additional configuration through jumpers
The system?s bus operates at standard speeds of 60MHz and 66MHz, which is multiplied by a factor to obtain the processor?s speed. The Pro 150 therefore operates at 60 x 2.5, while the 200 operates at 66 x 3. Most of the boards tested can handle multiplication factors of 3.5 and 4, which makes it theoretically possible to assemble machines that operate at 233MHz or 266MHz.
The usual PCI and ISA slots for expansion cards and a set of Natoma chips that will support forthcoming universal serial bus (USB) peripherals can also be found on the boards. The incorporation of connections for infra-red devices is also on the agenda.
Specific chipsets
The chipset serves as an interface between the microprocessor and the elements that make up the architecture of a PC, such as the memory, the input/output controllers and cards in the system slots. It handles the control signals required for any transfer of information to be carried out correctly.
The first generation of Pentium Pro chipsets are the 450KX and 450GX: the first is oriented towards high-performance workstations; the second, as a result of its extended multi-processing capacity, can be implemented in servers through OEM manufacturers.
The KK, also known as Mars, and the GX or Orion, use the same structure based on a data controller (DC), the other on a data path (DP) and a memory interface control unit (MIC) among other components. Depending on the configuration, there can be up to nine chips, and as for packaging there is the option of ball grid array (BGA) format, which incorporates more components in less space. The Orion allows up to four microprocessors to operate simultaneously in the same machine.
The most commonly used chipset is the 440FX, also known as Natoma. This group of second generation integrated circuits comprises three chips, considerably reducing the number of components needed to carry out the functions of the chipset. Its main features include the use of PCI competitive bus technology and USB peripherals support. It comprises a PCI controller and memory (PMC) and a data bus accelerator (DBX). In addition, the input/output sub-system, called PIIX3, is similar to the one used in the boards for Pentium micros with the HX and VX chipsets.
The types of memory which support this chipset are fast page mode (FPM), EDO and BEDO. The latest generation memories cannot be handled by these circuits.
All the chipsets referred to use an error correction and detection technique (ECC) which enables data to be handled more reliably.
To get the maximum out of the MMX technology on the Pentium Pros, Intel is developing the LX chipset which, among other features, will introduce an advanced graphics port (AGP) and Ultra DMA/33 techniques.
The Pentium Pro is available at speeds from 150MHz to 200MHz and the chip incorporates 256K or 512K of level 2 cache.
Undoubtedly, everyone is awaiting the arrival of the Pentium II, formerly known as Klamath. This will incorporate MMX technology, improve the performance of multimedia applications and may break the 200MHz barrier.
How the tests were done
Intel?s Pentium Pro processor is designed to work with 32-bit programs, and its performance nosedives with older applications. The tests have taken this into account.
The Pro?s exceptional 32-bit performance is achieved at the expense of the speed at which it can work with smaller packets of data, particularly 8-bit. Intel?s engineers assumed, in preparing the blueprints for the chip, that by the time the Pentium Pro appeared, all the operating systems and programs on the market would be 32-bit. As we all know, this is a far cry from the reality.
First, almost every user continues to run Dos programs ? the prime example of 16-bit programs. Second, Windows 3.x still accounts for a large number of users. Third, while there are a considerable number of Windows 95 users, in spite of Microsoft?s initial promises, the system has more than two internal modules which operate in real mode.
This detail was heavily criticised when Windows 95 first appeared, although Microsoft?s software engineers had little option because they had to strike a balance between almost total compatibility and greater performance. The results are clear for all to see, and although Windows 95 is not the perfect OS for many things, it is clearly superior to its predecessors.
The labs tests were carried out using W95, because a large portion of users will work with it or compatible applications.
In a separate group are the users of 32-bit operating systems such as Windows NT, OS/2 or the various flavours of Unix appropriate to Intel chips, such as SCO, BSD and Linux. In these cases, a Pentium Pro processor will prove beneficial and its capabilities will not be reduced in any way.
What we used
The best known and most reliable test utilities and programs for gauging a computer?s performance tend to be Dos applications in real mode. But they are not suitable as a means of testing Pentium Pro boards.
In order to be able to test the performance of basic boards for Pentium Pro appropriately, we considered what a typical configuration for this processor would be. First, we opted to include 32Mb of EDO Ram. In most cases users are likely to increase this amount to 64Mb, especially if they want to use the eagerly awaited Windows NT 4.9.
The graphics card used in the tests was a Winfast S600, which incorporates an S3 Virge chip with 2Mb of 35ns EDO Ram. Few cards can equal its performance for producing on-screen graphics with a frame buffer.
To install the software we used a 10-speed Pioneer CD-Rom, which is not particularly significant as it does not influence the test performances, but its high speed did make life a lot easier. For storage, we used a 1.2Gb Quantum Bigfoot and a 1Gb JTS Corporation hard disk. Both are typical of what is available on the market.
The only noteworthy element, at least with regard to equipment, is the processor. We opted for the fastest x86 processor Intel has made: a 200 MHz Pentium Pro with 256Kb internal cache. A 166MHz Pentium Pro with 512Kb cache was used as a reference point.
Test Results
Chaintech 6IDM
The basic board uses the Intel 440FX chipset and in spite of its modest performance, it shows the results of detailed manufacture. The design has not taken into consideration the configuration of the microprocessor?s operating voltage using jumpers, which means the supplied voltage control module has to be connected.
There are three ISA slots, three PCI slots, one mixed slot and a connector for a PS/2-type mouse. In addition, there is a three-pin board socket for the microprocessor?s fan. The cables for the serial ports are screened against noise.
Value-added elements include a disk containing utilities for the re-programming of the Bios and bus domain controllers. The board also has an infra-red connector compatible with HP and Intel modes, and USB peripherals support.
The Bios used on the board is Award with NCR support; the circuitry which integrates the clock in real time and the Cmos memory is from UMC. There is a keyboard earth jumper which should be opened to avoid interference between the board and other internal components of the PC.
Intel Venus
Any review of motherboards for PC platforms has to include Intel, the manufacturer responsible for producing the microprocessors and chipsets. The board examined here is the VS 440FX, better known as Venus, which uses an ATX design with the usual connectors for ports and PS/2 for keyboard and mouse. It provides three PCI slots, a few ISA slots and one mixed slot. In addition, there is an infra-red connector, but none for USB, in spite of the fact that the Natoma chipset supports two connections.
Voltage control is automatic and there is no need for a controller module. The frequency multiplier has a maximum factor of three for the Pentium Pro 200 MHz and there does not appear to be much room for extension.
As an option, the same board is available with an integrated Soundblaster Pro-compatible 16-bit Crystal sound adaptor. This can handle audio samples in full duplex ? which is very useful for connections through the internet.
Another Intel model for the Pentium Pro range is the AP440FX, the principal feature of which is that it is designed in LPX format. It incorporates the 16-bit Crystal sound card and a graphics adaptor, either the Trio 64+ or the Virge with 3D acceleration, both from S3. An older model, the Performance/AU, uses the 450KX chipset on an ATX board.
Asus P6NP5
Asustek offers one of the most extensive range of boards for Intel processors. The P6NP5 is designed around the 440FX chipset, but an older model, the P6RP4, incorporates the KX chipset.
The board frequency multiplier not only accepts a factor of 4 for a hypothetical chip operating speed of 266MHz, but also contemplates a factor of 5. In theory this would allow a chip operating speed of up to 333MHz. Voltage control is effected automatically on the board.
Controllers for bus arbitration and DMI configuration utilities are supplied on a disk which the company includes with all its basic board models. The DMI- compatible Bios is from Award.
All Asustek products incorporate a specific expansion slot known as the Mediabus. This PCI-compatible slot allows the installation of advanced performance cards. A maximum of four PCI cards and three ISA cards can be installed. This is a connection for a PS/2-type mouse and a channel for USB peripherals.
Soyo SY-6FA2
Soyo?s board incorporates the Natoma chipset, which led to faults with S3 graphics adaptors in the first versions. This has now been rectified.
The board format includes connectors for standard supply source and for ATX, which is selected by configuring a bridge from the board. There are three PCI expansion slots, a few ISA slots and a mixed ISA/PCI slot. In addition, connectors for infra-red and USB are present, as well as PS/2-type connections for a keyboard and mouse.
Intel?s Natoma chipset offers support for various types of memory including the traditional fast page mode, EDO or the more modern Burst EDO. This board also allows extra Dimm modules to be added, and there is a Dimm socket-base in addition to the typical sockets for 72-pin memory. This 168-contact Dimm socket can be 3.5V or 5V, and the voltage is specified using a jumper. The microprocessor voltage is set by inserting the corresponding controller into its socket.
There is no possibility of using chips which operate at more than 200MHz because the maximum frequency multiplier has a factor of three. The Bios is Award with NCR support.
Air P6NPI
This basic board model for the Pentium Pro has some professional features. To start with, it has the traditional controllers for serial ports, parallel ports, infra-red ports, PS/2 mouse, EIDE hard disk and disk drives. To this can be added two USB ports and an Ultra Wide Scsi controller from Adaptec. The board will support speeds up to 266MHz.
The presence of the two USB ports, which allow the connection of dozens of peripherals, is the start of a trend. One of the ports will be dedicated to high-speed peripherals and the other to slower peripherals.
The integrated Ultra Wide Scsi controller would ordinarily cost about the same as the board if bought separately. Ultra Wide Scsi peripherals can be connected using the 68-pin connector, and traditional Scsi peripherals can be attached using a 50-pin connector. A special card can be added with Raid functions.
The board format is ATX, so all the connectors are on the rear section. In this case there is no VRM socket-base since the voltage is adjusted using jumpers.
In most of the test categories the results were outstanding, although it is one of the boards that produced the faults with the Natoma chipset.
Iwill P6ANand P6NS
The P6AN is an ATX-format board with an Award Bios. It supports processor speeds up to 233MHz and comes with controllers for serial, parallel and PS/2-type mouse ports plus floppy disk and EIDE hard drives. In addition, there is an infra-red port and a USB port. Voltage is set using jumpers as there is no VRM socket; feed can come from an ATX source or a standard source.
As a special feature, this board has six 72-pin memory banks, which reduces the cost of large memory configurations while easing future expansions. In our tests, it occupied the top positions, except in some memory transfer tests, where it failed to stand out.
The P6NS overshadows the P6AN thanks to its Ultra Wide Scsi controller from Adaptec, to which a Raid module can be added. The other elements are identical, except there are only four memory sockets and the board will support processor speeds from 150MHz to 300MHz. This board has the easiest configuration method we found in this comparative study: a single jumper is located in the position corresponding to the speed of the chip.
QDI P6I440FX Commander
The most striking aspect of this board is undoubtedly the flexibility it offers when configuring the operating voltage of the processor. It can be selected automatically by the board?s circuitry or configured manually. The supply voltage can be set from 2.1V to 3.5V in stages of 0.1V using jumpers, although the voltage control module still has to remain in its socket.
The connection options are fairly comprehensive and include a socket for a PS/2 mouse, plus infra-red devices and two connectors for USB peripherals. There are three PCI slots plus a few ISA slots and one mixed slot. Finally, a CPU fan with a two-pin can be fed direct from the motherboard.
The Award Bios includes in its code the NCR 810 Scsi Bios and Adaptec 7850. Utilities are provided to reprogram the Bios for upgrades. The CMOS memory battery is inserted in a socket so that it can be easily changed.
Gigabyte GA-686NX
Gigabyte?s offering has a Natoma chipset and a design comprising four printed circuit layers, full of condensers, the operation of which is fairly correct. It is the only product for Pentium Pro chips in the company?s range.
The most significant feature of the board is the ease of its configuration: the system clock speed and the corresponding clock speed are set using a simple four-switch DIP. There is no need to connect a voltage control module as the board has an automatic control system.
The board uses the ATX format. There are external connectors for a keyboard and PS/2 mouse, two nine-pin serial ports (DB-9) and a parallel port. In addition, there are two supply connectors ? the traditional one and one for ATX sources.
Memory is fitted into the usual four 72-pin sockets, and there are three PCI slots, three ISA slots and one mixed slot for expansion cards. The chip for the clock in real time is Dallas and the port controller is UMC. The Bios is from Award. There is also an option to for USB and infra-red connections.
Plexus Pro-66
Plexus, formerly Star Micronics, is one of the most respected manufacturers on the market. The Pro-66 is a basic board which supports processor speeds of up to 266MHz. It comes with the usual controllers ? hard disks, disk drives, serial and parallel ports and PS/2 mouse ? as well as an infra-red port and a USB port.
The board format is mixed ? it has connectors for ATX or normal source ? and comes with an AMI Bios and a socket for the system?s battery, which can be changed even more easily than a clock battery.
Most notably, the board has a VRM socket, and it comes with the corresponding cables for the disks, the manual, a drivers disk and a VRM module for voltage control. The drivers disk includes utilities for DMI, upgrading the Bios and bus mastering.
Configuration is fairly simple and effected using a single set of DIP switches.
In the tests carried out, this basic board fell behind in terms of memory access both in Dos and Windows, but in the rest of the tests it occupied the top positions or, as in the case of Linux, led the field by some distance.
ETI Super P6DNE
This baby AT format board incorporates connectors for keyboard, serial ports, parallel ports and PS/2 mouse port, as well as controllers for hard disks and disk drives. Rather unusually, the first set of ports come with extensions for coupling them to outlet sockets in the case. The board can use processors from 150MHz to 200 MHz, and there is a VRM socket and corresponding module that occupies a minimum of space. It also has an infra-red port.
What is most striking about this board is that it has six memory banks, instead of the usual four, offering a variety of possibilities for memory configurations ? for example, where two 32Mb modules are cheaper than a 64Mb one. This arrangement can result in a lower price while offering greater flexibility at the same time.
In the tests, this board turned in some fairly strange results. With the 200MHz chip it led the field in nearly all the tests, but it came last when fitted with the 166MHz chip, possibly because of a fault in the frequency multiplication circuit. This may have ramifications for users seeking maximum system speed.
Problems with the Natoma
The chipset used in all the boards in this report, partly because it was the first to appear on the market, is the 440FX from Intel, also known as Natoma. Other options will shortly appear on the market, such as SiS or Via Chipsets, but for the time being the boards for Pentium Pro use only the 440FX. In some cases this does not work well with video cards which include an S3 Trio64V+ or S3 Virge chip ? chips that are present in most of the equipment which is currently available. The problem manifests itself as snow on screen.
Two of the basic boards with an AMI Bios, which include support for Atapi peripherals with PIO Mode 5, didn?t work well with either of the hard disks used in the tests, and we had to force the work mode down to a lower level. By chance, these boards also demonstrated the faults with the Natoma chipset, as did an initial board from Soyo, which was replaced with one which didn?t exhibit the problem.