MOTHERBOARDS - All aboard
Motherboards may not seem the most interesting of components, but the speed and design of PCs in the future depend on them.
Although few PC components can be said to be in any way sexy, but the speed and design of PCs in the future depend on them. undoubtedly the least sexy of the lot has to be the motherboard. In the eyes of most customers, the motherboard is a largely passive device, its sole function being to act as the glue holding together all the components that do the 'real' work.
That's as maybe, but for this year and many years to come it will be developments on the motherboard that will essentially determine how fast PCs run, how they're assembled and what they look like.
For resellers looking to offer clients a cheaper alternative to throwing out their PCs and replacing them with new ones, the options available are considerable. But keeping abreast of the different technologies and compatibility issues is no mean feat. What at first may seem like a manageable and profitable job - replacing 50 old motherboards with 50 new ones - could quickly turn in to your worst nightmare. Simply slotting a network card onto a new board could cause a big compatibility headache, resulting in serious downtime and a less than happy customer.
Back in the old days, life was a lot simpler. All traditional motherboards were derived from the original IBM AT, although a smaller version, dubbed Baby AT, became the preferred form factor in later years. Today, the most common motherboard form factor is Intel's ATX design.
Although ATX and Baby AT boards are approximately the same size, the ATX board is rotated 90 degrees within the PC's case, allowing easier access to internal components. This offers several benefits, most of which relate to moving the processor, Simm slots and other components to the right of the expansion slots. This has the advantage that the CPU is positioned closer to the power supply and its cooling fan, helping regulate the temperature of the CPU.
The new orientation also reduces clutter inside the chassis, making the interior of a PC much easier to access. ATX helps eliminate internal tangles by enabling motherboard ribbon-cable connectors for floppy and hard drives to be placed where they belong - near the drive bays.
However, to muddy the water further - or to help plug a necessary gap, depending on your technical persuasion - Intel has confirmed yet another form factor. The WTX mid-range workstation motherboard and chassis specification effectively fills the void between industry standard PC and server components.
The specification includes support for workstation features such as dual processing, large system memory, Accelerated Graphics Port 4X graphics specification and AGP Pro graphics cards, and high-bandwidth I/O. It also complements processor advancements such as the Xeon processor and should result in a simplified design process and reduced development costs for OEMs manufacturing Intel-based workstations.
The most recent trend in mother-board design has been the shift to integrating peripherals directly on the motherboard itself, a move undoubtedly accelerated by the continuing downward spiral in PC prices. MicroATX motherboards, a development of the ATX standard, are smaller in size than ATX boards but are backwardly compatible with ATX cases. They are generally limited to four slots, but have onboard controllers for I/O, video graphics and sound. The high degree of integration means Micro-ATX motherboards usually require only 90W-145W power supplies. The motherboard's reduced size also allows it to fit into smaller and lighter cases.
The MicroATX motherboard, power supply and case can save resellers about £15 on the motherboard and up to £25 on the case - a significant saving in the low-margin, low-cost PC market. Such boards also help cut inventory costs, as there is no need to stock various add-on cards. And since the different components are integrated, there are no software driver compatibility issues.
The downside of heavy integration is that it is difficult for resellers to differentiate their products. Some system integrators have also reported hardware resource clashes when they add devices such as network cards.
Such clashes can be difficult to resolve, simply because the integrated devices can't be physically removed, only disabled.
Intel plans to integrate additional technologies, such as Rambus In-line Memory Modules (Rimms) and soft modems, onto Pentium III motherboards this year. According to US reports, the chip giant will also continue to add technology from other product groups, including Accelerated Graphics Port (AGP), PCI audio and Lan-On-Motherboard (LOM).
Low-end boards, based on the Celeron chip, are predicted to feature varying levels of integration. Plans for one Celeron board, code-named Cayman, include an integrated soft modem, AGP and PCI audio, while the Augusta board will include AGP, PCI audio and LOM. The boards are expected by summer.
At its Developers' Conference in Palm Springs in February, Intel previewed its FlexATX motherboard. This is about 30 per cent smaller than the MicroATX and is designed to fit into a variety of different form factors. The samples shown included the 810 Whitney chipset, plus a Socket 370 Pentium III PGA socket, PC100 Dimm memory, USB ports and the audio/modem riser.
Just as it dominates the CPU market, Intel also exerts a stranglehold on the chipset market. The company has several AGPsets in its current range. The Intel 440BX AGPset supports the 100MHz system bus for the faster Pentium II and Pentium III processors. The 440BX handles up to 1Gb of Ram and does AGP graphics. The previous 440LX AGPset brought support for AGP, 33Mb/sec UDMA hard drive burst rates and fast SDRam to the Pentium II platform. The 440LX supports Pentium II processors only up to 333MHz.
Intel also markets the 440EX, a pared-down 440LX designed for the Celeron.
The 440EX only offers limited expansion slot support, however.
Both Silicon Integrated Systems (SIS) and Via Technologies manufacture chipsets compatible with Intel's line, some of which provide additional capabilities. Key competitors to Intel's chipsets include the Via VP2/97, which directly targets the old 430TX and supports several Ram types and UDMA. Via's Apollo MVP3 adds AGP to the mix, as well as support for a 100MHz system bus to benefit CPUs like the K6-2, the M II-333 and the forthcoming WinChip 2. Via recently announced the Apollo Pro, a Pentium II-compatible chipset that supports SDRam and AGP, as well as 100MHz-bus Pentium II chips.
Most notable from SiS is the SiS5601 chipset, which supports Pentium II CPUs along with the 100MHz bus and AGP. The company also offers the SIS5600 for the Celeron, and for the Socket 7 world, the AGP-supporting SiS5591. Acer Labs (Ali) offers, among other sets, the AGP and 100MHz bus-capable Aladdin V.
The AGPset for the next round of Pentium III processors will be the Intel 820, also known as Camino. The i820 is a crucial piece of silicon because it enables systems to move to a faster, 133MHz frontside bus (FSB) and provides the interface for Direct Rambus DRam, a long-awaited high-speed memory that is expected to boost PC performance in 1999.
While processing power may have increased 200-fold since the 486 some 10 years ago, memory performance has only increased by a tenth of this.
This lag has got so bad that processor speed increases have become almost pointless. Rambus aims to deliver more than 10 times the performance of today's memory subsystems while keeping costs down and providing a means of reusing SDRam Dimms. The i820 chipset will support either today's SDRam Dimms or direct RDRamSRimms. An i820-based system will support up to 1.5Gb of SRimm memory or 1Gb if Dimms are used.
However, persistent difficulties with Direct RDRam manufacturing yields and issues related to clock IC timing and printed circuit board impedance have resulted in significant production delays. After a long period of denial, Intel confessed in February that the 800MHz Camino chipset would be delayed until September and in the meantime, a Camino chipset that supports slower, 600MHz Rambus memory will be launched in June.
In another interim move, the 440BX chipset has been given a new lease of life and is set to be validated to support Pentium IIIs running at up to 700MHz. Intel is also said to be working on another chipset, known as the Intel 815, which supports a legacy 100MHz SDRam interface.
The delay with Camino has upset many OEMs and DRam vendors - they have the Rambus product ready to ship. As a result, many PC OEMs are reportedly hedging their bets, doing parallel development for both D-RDRam and PC-133 for desktop PCs.
The workstation version of Camino - the i840 - will come in two flavours: the standard dual processor variant for Pentium III or PIII Xeon and the high-end, four-way i840-QP for PIII Xeon alone. The new chipset will support AGP4X, AGP Pro, both RDRam and SDRam memory, dual PCI buses (32/33 and 64/66), and offer 3.2Gb memory bandwidth.
Other chip makers have developed integrated systems, such as Cyrix's MediaGX processor and SiS' 530 chipset, but now Intel has entered the fray with the upcoming 810 Whitney chipset. This will integrate an i752 graphics core into the north bridge, which connects the CPU to the main memory bus. Whitney will also integrate an audio controller, Ultra/ATA EIDE controller, USB and a new bus called LPC (low pin-count) which will handle legacy devices such as serial and parallel ports, keyboard and mouse. Support for the ISA bus is absent, meaning all devices in a Whitney-based box will connect via PCI or USB.
These systems can be configured to give the i740 its own frame buffer, or the graphics accelerator can use system memory. Whitney will have a 100MHz FSB and a third processor in its chipset: a 'firmware hub' storing the Bios software of both the core logic and graphics cores.
Intel claims this will save mother-board OEMs about $25 a board - roughly 20 per cent less than the cost of a device that uses only discrete components.
And because motherboard, audio and graphics card suppliers typically pass their component costs on to OEMs, a more highly integrated board using the 810 architecture could knock as much as $50 to $100 off the price of a PC.
The launch of the Pentium III confirmed Intel's commitment to the Slot 1 architecture, but it's becoming slowly apparent that this CPU form factor will eventually turn out to be no more than a blip on the processor roadmap. There's a strong likelihood Intel will return to using the Pin Grid Array (PGA) form factor that the vast majority of CPU manufacturers currently employ.
While Intel's mainstream processors continue to use Slot 1, the 'three dwarves' - as Intel's CPU rivals, AMD, Cyrix and WinChip are quaintly termed - continue to use the old Pentium Socket 7 ZIF Socket (dubbed Super Socket 7) for their processors. Despite Intel's direst predictions, this hasn't hindered processor speeds unduly and the fastest CPUs compete directly with Intel's finest silicon. Super Socket 7 motherboards run the popular AMD K6-3 3Dnow! at 450MHz, with an FSB running at exactly the same speed as the latest Pentium II and Pentium III motherboards - 100MHz. And its use by the likes of IBM and Compaq vindicates Super Socket 7.
The problem for Intel is that Slot 1 is still a relatively expensive solution. In a bid to compete with AMD and Cyrix on price, it recently reverted to a low-cost socket technology, Socket 370, for its latest Celeron releases (a standard Socket 7 socket has 321 pins). It has gradually shifted the whole Celeron range over from Slot 1 to Socket 370.
The final nail in Slot 1's coffin will come with the shift to an 0.18mu m process later this year, with the release of the 600MHz or 667MHz Pentium III (aka Coppermine).
This makes it much easier to incorporate the L2 cache on-chip, something AMD has already achieved with the K6-III.
Intel had previously cited the prohibitive cost of putting the L2 cache on-chip as the reason for switching from the Pentium Pro/Socket 8 to the Pentium II/Slot 1, which has the L2 cache off-chip. Apparently, incorporating the high-speed cache on the same die as the CPU was a little too hit and miss back then - sometimes the cache would work and the CPU not, or vice versa, meaning that that particular chip, although '50 per cent' OK, was still destined for the dustbin.
Placing the chip on a daughtercard, although imposing a performance penalty, avoided costly production errors such as these. However, the adoption of the 0.18mu m process will see Intel turning full circle and using the Socket 370 architecture (or something similar) for all future processors. Some reports have predicted that by the end of the year the Pentium III will shift over to a socketed PGA form factor.
Perversely, AMD seems to be adopting precisely the opposite tack with its K7 processor. Due to be launched in June, the K7 will fit in a Slot A connector. Although physically identical to a Slot 1 connector, Slot A isn't electrically compatible with it. This is because AMD is shunning Intel's P6 GTL+ bus protocol in favour of Digital's Alpha bus protocol, EV-6. EV6 can run at 200MHz and much higher - twice the speed of Slot 1/GTL+ - and as a result the K7 will be the first CPU to take advantage of high bandwidth (1.6Gbps) memory architectures such as Direct Rambus.
To put it another way, Pentium III can't make full use of the bandwidth offered by Direct RDRam.
AMD chose Slot A for a variety of reasons. According to Paul Ridgeway, UK's marketing manager for hardware infrastructure at AMD: 'Proven by Digital, it's less a 200MHz bus and more an interconnect technology, with plenty of headroom for future speed increases. It allows a range of solutions based on the size, speed and type of cache required - Slot A allows AMD to tailor this for the market.
'Slot A is also superior to Slot 1 in SMP environments. Under Slot 1, each CPU has to share access to the chipset, but under Slot A, each CPU has direct access to the chipset. However, it doesn't preclude a switch to other form factors in future.'
K7 will, because of its high clock speed, have plenty - 128Kb - of Level 1 cache (64Kb data and 64Kb instruction cache). K7 will come with 'backside' L2 cache: initial versions will feature 512Kb, but AMD is planning K7 versions with between 2Mb and 8Mb, using additional external tag Ram as Intel does in its P6 CPUs. The L2 cache speed will range from 1/3 to full CPU speed and AMD plans to use 'normal' as well as double data rate (DDR) SRams for this cache. It will initially run at 500MHz.
With more technologies being included on motherboards, it is going to be an interesting market.
THE IMPACT OF PC99
Early samples of motherboards that comply with the Microsoft/Intel PC99 specification - all based on the delayed Intel Camino chipset - were unveiled at Comdex and CeBIT 99. Board maker FIC previewed its KCI-6111 motherboard, which has five PCI slots and no ISA slots at all. It has other compensations, though, including USB, an AMR connector (audio and modem riser module), IEEE 1394/FireWire, hardware security, 4X AGP, Rambus and 100/133MHz FSB support.
ISA slots are not the only legacy bus to come under the PC99 axe. For example, only printers - no other parallel port devices - are 'allowed' to access COM or LPT ports: printer makers are encouraged to use USB or 1394. The venerable PS/2 mouse and keyboard ports are also to go, superseded by USB. Proprietary hardware for games is forbidden and even IDE isn't sacrosanct - under PC99, ATA and ATAPI devices are to migrate towards 1394. SCSI remains relatively safe, though, in the short term.
PC99 defines two types of PC, the consumer and the office PC. The former will have a minimum of a 300MHz CPU, 32Mb of Ram, OnNow support, two USB ports, 3D graphics and an internal V.90 modem.
The 'Recommended' list is somewhat tastier - on top of the aforementioned, the following is to be added: a total of 64Mb, 1394, Device Bay, IrDA infra-red, AGP, TV facilities, PC99 Audio and support for fast comms, such as ADSL or cable.
INTEL MAPS OUT THE FUTURE
By the middle of next year the industry could be seeing PCs shipping with a much faster version of USB. Work on the USB 2 specification has begun, with a final draft due in September. It will offer between 10 and 20 times the throughput of USB 1.1's 12Mbps - that is, a data transfer rate of between 120 and 240Mbps. Some US sources have speculated that the bus could deliver even more throughput, perhaps as much as 300Mbps.
If 1394 pans out the way Intel has predicted, it will become a Consumer Electronics technology used to interconnect home entertainment systems, digital cameras and the like.
At the recent Intel Developers' Conference in Palm Springs, the chip giant outlined its take on the I/O roadmap.
Intel doesn't see any significant changes in desktop I/O for the next five years or so, just refinement of existing technologies. It maintains that internal storage requires its own private bus and that this will be delivered by a further refinement of Ultra DMA, using the ATAPI protocol.
ATA66 (aka Ultra DMA/66) will last through to about 2001, to be replaced by 'Future ATA', which Intel predicts will feature a 1Gbps throughput.
Interestingly, despite all the developments in SCSI, Intel sees it being superseded, at least for external storage, by USB 2.0 by the year 2001.
The possibilities opened up by these high-speed Plug and Play interfaces will also influence the way system units are assembled. A new hardware form factor/interface involving both USB and 1394 has been developed by Compaq, Intel and Microsoft. Called Device Bay, it is similar in concept to PC Cards. Device Bay will consist of a connector slot in three standard form factors, including two small enough for notebook computers. The back of each slot will contain connectors for USB and IEEE 1394. A Device Bay peripheral can use either bus to provide hot-swappable operation. Typical uses of Device Bay would be for additional hard drives, DVD-Rom drives, back-up and removable media devices, and so forth.
These changes should bring expandability to the outside of the case.
Future PCs will let you add almost any new capability without opening the case. And 'hot swapability' means you'll be able to simply plug these devices into their slots and they'll work without rebooting.