Intelligence in motion: the Pentium 4 Mobile processor.

Consumer demand for mobile computing performance — enough to reckon with the geographically-challenged desktop — is driving industry to deliver the goods (yesterday, thank you), but it is only now that we are beginning to glimpse the fruit of serious R&D investment in this field. And how fecund it is.

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By  Kate Concannon Published  April 29, 2002

Introduction|~||~||~|Consumer demands are simple: we want virtuoso performance; seamless, comprehensive connectivity; consistent battery endurance to rival the driving thump of bunnies on drums; and we want it in a form that preaches the values of lightness and thinness with all the fervour of a nutter atop a soapbox. But, until now at least, technology has stalled the brave leap beyond limited, conventional configurations.

A quick glance at chunky, onerous laptops from down memory lane powerfully illustrates just how far we have come over the years. But, for every challenge that the industry overcomes, consumer use evolves to create new challenges. “Today, what you’re getting in a notebook PC, fundamentally, is portable computing, any time, anywhere,” explained Anand Chandrasekher, vice president for Intel’s mobile platforms group. What we really want, however, is connected computing for everyone, anytime, anywhere.

With the four vectors of mobile computing — performance, connectivity, battery life and form factor — and dedication to technological development close at heart, Intel has established a mobile enabling program with broad industry support. It is with a shared goal and flexibility — not proprietary, rival systems and visions — that organisations are best able to deliver to end-users their very demands.

But whilst this program represents a long term project, there exist, just around the corner, some key technologies that are set to get us up and sprinting. And who should be spurring the deployment and enhancement of these technologies as they are getting ready to climb off the lab bench? Intel, of course, who reported R&D spending (excluding in-process R&D) of $3.8 billion in 2001. That figure looks set to hit the $4.2 billion dollar mark in 2002, with the funding directed towards expanding its computing and communications product folio.

Set for market deployment within the coming months is Intel’s next contribution to the world unchained: the Pentium 4 Processor-M. All eyes are on this next best thing in mobile computing; it may just yield enough powers of persuasion to get even the stragglers among us upwardly mobile.

The reason is without complexity: the processor has been specifically designed to bring all the benefits of Pentium 4 powered desktop computing to the mobile platform — without bringing bulk to the party too. (As any laptop-lugging ranger will tell you, you can never get too thin or too light.)

“The introduction of Pentium 4 Processor-M brings to mobile computing the performance users have come to expect from the Pentium 4,” said Chandrasekher. “Together with the Intel 845 chipset and advanced power management technologies, this delivers an optimal balance of high performance and long battery life for today’s mobile PCs.”

The Pentium 4 Processor-M is based on 0.13 micron process technology, a manufacturing term which refers to the size of the microprocessor’s poly-silicon gate. Direct relationships exist between gate size and both the processor’s speed and its power requirements: the smaller the gate size, the lower the power consumption; and, inversely, the smaller the gate size, the faster the processing speed.

||**||Micro-architecture|~||~||~|Beyond this boost, however, much of the P4 Processor-M’s performance strength is drawn from a cunning new draught on the micro-architectural drawing board, dubbed NetBurst micro-architecture.

NetBurst features a number of specific technologies that well accommodate key mobility vectors. The initial Pentium 4 Processor-M clocks a processing speed of over 1.5GHz and, coupled with the 845 chipset, is solidly supported by a 400MHz system bus to ensure swift throughput and keep pace with the rapid processing speed — thus making the clockspeed improvement effective in practical terms. The system bus delivers a high-bandwidth connection between the Pentium 4 processor and the platform, which triples the bandwidth of Pentium 3 based systems.

Also supported by the 82845 memory controller hub (MCH) is PC133/DDR200/ DDR266 SDRAM memory, which enjoys wider data paths afforded by the novel architecture. Flexible memory refresh technology enables optimum performance. While PC133 SDRAM provides support for the highest volume, most cost-effective memory in use today, DDR 200/266 SDRAM provides the means for high performance in multimedia applications with all the cost-benefit of SDRAM architecture.

Not quite up to speed with the promising RDRAM — dual RDRAM memory channels are implemented in the 850 chipset, originally developed with the Pentium 4, achieving a peak memory bandwidth of 3.2GB/sec — it means for the end-user a value-priced product, performing sufficiently until the cost of manufacturing, and so the piece itself, is reduced.

Two cache enhancements are also on board to use storage space more effectively, and thus increase processing speed. In addition to a 8KB data cache, a level one execution trace cache, which stores 12K of decoded micro-ops, is incorporated in the processor. Notably, 0.13 micron Pentium 4 processors make available 512KB L2 advance transfer cache, which is synchronised with L1 cache. By removing the decoder from the main execution loop, space usage is optimised as branched instructions are not stored. Recovery time after a branch prediction error is thus reduced too.

Branch prediction is also improved with NetBurst architecture. Advanced dynamic execution provides a prediction algorithm, which uses a 4KB branch target buffer, capable of storing more detailed history, to produce more accurate predictions. This technology is also designed to complement the greater pipeline depth given by hyper pipelined technology. Here, pipelining is twice the depth of that provided by Pentium 3 micro-architecture, and should afford enhanced performance, scalability and frequency, enabling instructions to be queued and executed as quickly as possible.

The Pentium 4 Processor-M will also offer surprising multimedia performance, with streaming SIMD 2 extensions, expanded 128-bit floating point register, and 1.5V AGP4X interface for the latest graphics devices. The 82801BA I/O controller hub (IHC2, also packed into the chipset, provides direct connection to the graphics and memory for faster access to peripherals.

||**||Wireless connectivity|~||~||~|But what of connectivity? The convergence of communications and computing technology holds the key to the future of wireless connectivity in notebooks. “Wireless will always be on for notebooks,” said Chandrasekher, who also reported that many of the first notebooks to feature P4 Processor-M will feature built-in 802.11a/b and Bluetooth connectivity.

“It will usher in a new era of computing, not unlike what happened with cell phones. Cell phones really untethered users, and notebooks offer the ability to keep in touch in a much broader sense than the telephone did. This represents a key inflection point for Intel and the industry at large.” At this IDF, Kurt Sehnert shared Intel’s vision of a future where wireless access is as ubiquitous and seamless as that of cell phones today.

Chandrasekher also described some of the P4 Processor-M’s wireless potential with an ad-hoc, point-to-point connection demonstration, requiring no access point and allowing two users to interact via the Intel Pro 5000 wireless card, capable of compressing and securing data with 196-bit encryption.

Some future also lies in the arrival of USB 2.0 On the Go. By this, data can be transferred at 480MB/sec, and, more importantly for mobile devices, a device can act alternately as host and peripheral.

Pat Gelsinger, Intel’s chief technology officer, expounded upon the potential applications of this networking platform in his own keynote address. Along with Dr David Culler, director of Intel Research Lab at UCLA, Gelsinger demonstrated a multi-node, wireless ad-hoc sensor network that self-assembled and reconfigured automatically.

Integrating this technology into low-cost, sophisticated silicon sensors, would enable all manner of new applications. Gelsinger appealed to developers and engineers to start thinking creatively about the technology’s potential, stimulating the industry mind with promising ideas of smart farmlands, equipped with silicon sensors embedded in the earth to manage fertilization and irrigation, smart clothing and smart infant blankets, which could monitor an infant’s vital signs.

But as “seamless, always-on wireless connectivity that works securely… becomes more predominant and ubiquitous, it is going to put pressure on battery life.” And security issues. As Microsoft’s corporate vice president, Jawad Khaki, aptly stated: “always-on means always under attack.”

While it is up to industry and the mobile enabling program to define security solutions, the impact of connectivity upon battery life is already being tackled head-on. The P4 Processor-M and 845 chipset incorporate two key technologies that greatly reduce the power consumption.

SpeedStep technology allows the user to control the frequency (by changing bus ratios), thus reducing or increasing power use as required. Deeper Sleep alter is a power management mode, by which the processor’s power consumption is minimised when a period of inactivity is sensed. This is coupled with QuickStart, which speeds up the resume time once a notebook ceases to be idle.

||**||Banias: the next mobile processor|~||~||~|However, the major hurdle in power consumption still remains: the LCD. Required to refresh itself around sixty times each second, regardless of whether it is in use, the screen eats through battery power like fungus through a foetid sock, and represents around 40% of battery consumption.

This suggests that the real revolutions in prolonging battery life will come with the evolution of displays, and Chandrasekher predicts that this is likely to involve a 3-5 year wait. In the meantime, Intel is exploring a number of exciting alternative energy sources and fuel cells for notebooks, which may allow the user to ‘fill up’ on the spot rather than wait for a standard battery charge session to transpire.

This leaves form factor. The P4 Processor-M processor and chipset has been designed to be implementable in both full form and thin, lightweight notebooks. With more power comes greater heat generation, which in turn necessitates more effective heat dissipation systems. Developments on this front may prove somewhat influential in the form of future devices.

The Pentium 4 Processor-M will be widely available in a matter of months, but where does the future of mobile computing lie? The mobile enabling program is a multi-year program consisting of three main elements. Platform guidelines are the first issues to be addressed; then form factor, wireless connectivity and performance; and finally platform enabling.

In the meantime, however, while industry strives to come to terms with the demands the mobile vectors place on the products end-users require, Intel has a bun in the oven that’s due to brown nicely in early 2003.

Banias is the new family of processors destined for the mobile market place. The first processors to be built ground-up for this very platform, they promise a comprehensive approach to dealing with the matters at hand: connectivity; battery life; form factor, and, of course, performance.

Performance and connectivity look to be the first vectors to thrive, coming into their own. Battery life and form factor may have to wait a little longer, though Intel’s extraordinary display of concept notebooks, which aroused nothing less than a press riot at their IDF unveiling last month, will no doubt provide much needed inspiration to manufacturers seeking form appeal.

The key technology integrated in the Banias and Odem chipset combo that promises to boost performance significantly resides in hyperthreading. Banias will be the first processor to usher into the mobile platform this technology, which revives hope in the future potential of silicon.

Essentially, hyperthreading utilises unexploited circuitry on the Pentium 4 in such a way that it convinces an operating system that is actually a dual processor. This allows a chip to run instructions from one application through its floating point unit, and parts of another through its integer unit.

||**||Future mobile computing|~||~||~|“A chip with hyperthreading won’t equal the computing power of two Pentium 4s,” said Paul Otellini, general manager for Intel’s architecture group, who demonstrated hyperthreading technology at IDF — nor will it equal the hefty cost of a dual processor. “The performance boost, however, is substantial.” Although no official statement has been issued at this time, it’s entirely possible that Banias processors will be built using 90 nanometre manufacturing technology.

According to Otellini, this turbocharged processing power will become essential to meeting future PC usage patterns: “there are lots of tremendous applications on the horizon that will consume the MIPS [millions of instructions per second]. Gigahertz are necessary for the evolution and improvement of computing.”

Case in point: the use of PCs, both desktop and notebook, to decode HDTV as the digital universe converges, at a point where PCs, wireless devices, home appliances and consumer electronics meet and communicate.

Gelsinger also shared a possible future model for computing. He suggested there may come a time when RF is fully integrated on chipsets to provide all manner of connectivity options, such as wideband, which Intel is currently exploring and which may come into play within the next five years.

Gelsinger also briefly discussed Intel’s research in micro electro-mechanical systems (MEMS), silicon radios and intelligent roaming software, with a view to enabling broad deployment of these wireless, “always connected” communications eventually.

“We see a time when there’s a radio on every chip we make, making wireless communications more ubiquitous,” he explained. In time, it is envisioned that these silicon-based technologies will become small enough to facilitate the production of cell phones no bigger than an earring, for example.
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