The Atom processor is based on the Intel Atom micro-architecture, which was designed to achieve high effi ciency in terms of performanceper- Watt while maintaining full compatibility with the Core 2 Duo instruction set and architectural features such as HyperThreading, Virtualization technology and Intel Digital Media Boost (SSE3). It's currently based on the 45nm high-k process, but it will shrink to 32nm in 2009. Low power consumption is achieved using a range of power management techniques.
Competition from VIA and ARM
According to Brown, VIA's current products aimed at the MID market are based on the C7-M ULV processor. The VIA C7-M ULV provides x86 support via an in-order execution architecture and is offered in clockspeeds of 1.0GHz, 1.2GHz and 1.5GHz. VIA claims that this provides enough processing power to run devices based on full operating systems such as Windows Vista, XP or a mainstream Linux distribution. Like the Intel Atom, high performance-per-Watt is stressed, with power consumption figures ranging from 3.5W to 7.5W.
However, while Intel quotes average power consumption figures (which take into account the fact that the processor will often be idling), figures for the C7-M LV look much higher. This is because they relate to operational power. In reality, the two families are closer together than the figures alone suggest, although comparisons of average power will have to wait for the launch of the MID platform in numbers, when a comparison of performance-per-Watt will be much easier to establish.
Interestingly, there was no mention of a Nano derivative, despite previous indications from a senior VIA spokesperson that it would be used in this context. If and when a sufficiently low-powered version of the processor does become available, it shows every sign of being the first MID processor to feature potentially more efficient out-of-order execution.
Today, it's ARM's V6 architecture devices – such as the ARM11 – that power the Nokia N810, iPod Touch, and smartphones like the iPhone, all of which ARM consider to be MIDs. The architecture will continue to be used in new products of this type. However, for mini-notebooks and platforms closer to what most people think of as MIDs, processors with ARM's next generation V7 architecture, which includes the Cortex-A8, are being promoted.
The main difference between the ARM11 and Cortex-A8 is performance – ARM's figures show the Cortex-A8 achieving about twice the amount of work for the same clockspeed. This has an obvious benefit in terms of the all-important performance-per-Watt. ARM says that the Cortex-A8 range will start showing up in third-party products later this year. ARM claims that the Cortex-A8 has similar clock-for-clock performance as Intel's Atom, and that in addition to Windows Mobile, it can run the full desktop Linux operating system.
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It's said to scale in speed from 600MHz to greater than 1GHz and offers a number of architectural features perhaps unfamiliar to those who are more used to looking at Intel data sheets. This includes Neon technology for multimedia and signal processing, Jazelle RCT (Real-time Compilation Target) technology for efficient support of both ahead-of-time and just-in-time compilation of Java and other bytecode languages, and Thumb-2 technology for enhanced code density and performance.
ARM claims that this new processor can meet the performance requirements of mobile devices with a power budget of less than 300mW. As in the case of Intel's figures, this is an estimated in-use average rather than a peak power consumption figure. Where the Cortex A8 differs from both the Atom and VIA's C7-M ULV, however, is its lack of x86 support.
It's important to note that ARM's product is quite different from those offered by Intel or VIA. Whereas these latter two companies are selling chips – that is, pieces of silicon – ARM is licensing processor cores that their silicon partners, which include TI, Qualcomm, Samsung, Nvidia, Freescale, Marvell and Broadcom, integrate into a SoC (System-on-Chip) that is then sold to MID manufacturers.