Wasabi Roll: To ARMs, to ARMs, the British are Coming!

The British Invasion was a phenomenon that occurred in the mid 1960s when a group of rock and pop music acts from the United Kingdom, as well as other aspects of British culture, became popular in the United States. Bands such as The Beatles and The Rolling Stones would get their start during this time and go on to make a lasting impact on the American music scene.

Well once again, in the micro-processing world, to Intel's dismay, we find ourselves in this position as America embraces ARM Holdings, in Cambridge, England, which thanks to its vast ecosystem of partners has established near-complete dominance of the market for the core logic inside smartphones and tablets. 

In short, in the micro-processing world, up till now, you'd find two dominate players at opposite side of the spectrum; however, with ARM closing the performance gap, and addressing the power consumption issue along the way, we find these two giants beginning to clash.

ARM

Recently, ARM announced its new 64-bit processors, Cortex-A57 and Cortex-A53, that deliver higher performance at either the same or lower power levels compared to ARM processors today. You may have heard of ARM's Cortex-A57 under the codename Atlas, while A53 was referred to internally as Apollo. The new Cortex A57 and Cortex A53 processors follow ARM's Cortex A15 and Cortex A7, respectively. The A53 delivers the same performance as its predecessor, the Cortex A9 used in Nvidia's Tegra 3 chipset, but it'll be just a quarter of the size. The A53 and A57 being 64-bit processor means that memory space will be unlocked for higher capacities, so this will be critical for systems running Windows RT that need more memory. Processors from AMD and Intel have been 64-bit for some time now, so ARM is closing the technological gap a bit with the release of this new processor series.

Why is this announcement significant? ARM’s camp are eyeing a US $50 billion server market, fueled by the rise of social networking and cloud computing. ARM says that the Cortex-A57 will offer performance improvements of up to 30% over a Cortex-A15, which already out performs the Intel’s Atom initial offering, when implemented in the same 28-nm technology; 20-nm versions are said to be as much as 50% faster. However, Cortex-A57 SoCs will likely only become commercially available in 2014.

Similar to their 32-bit counterparts, the A57 and A53 can be used independently or in a big.LITTLE configuration. As a recap, big.LITTLE uses a combination of big (read: power hungry, high performance) and little (read: low power, lower performance) ARM cores on a single SoC. For example, for hi-end tasks the 57 can be used and for low end processing, like phone calls, the 53 would be tasked. To give you some perspective, compared to a 600MHz Cortex A8 (similar to the Exynos 3110 found in the Apple iPhone 3GS, launched in June 2009) etched on a 65nm processor, a 20nm quad-core A57/A53 combo will perform 16.5x faster, while consuming only 30 per cent more energy.

Note the energy reference. The demand for energy-efficient chips is reshaping the industry. As the PC market flattens, Intel aims to capture a sizable chunk of the rapidly growing mobile market, which rose to nearly half a billion smartphones in 2011.  

Dell and Hewlett-Packard already offer prototype ARM-based servers for testing to customers looking to deploy ARM servers to cut energy bills. However, Intel is also tweaking its low-power Atom processors to work in cloud servers and will release new Atom S-series chips for microservers later this year.

Intel

Now Intel is not taking this lying down, they are offering the Atom Processor Z2760 announced last month, formerly codenamed Clover Trail, this new mobile processor runs up to 1.8GHz. Other specs for the Z2760 include integrated graphics with up to 533MHz graphics core frequency and hardware acceleration support for 1080p video encode and decode. It offers support for one internal MIPI-DSI or LVDS display in addition to one external HDMI 1.3 display. Loaded with Intel Burst and Hyper-Threading Technology, the Z2760 comes with an integrated 32-bit dual channel memory controller and LPDDR2 support and 800 MT/s data rates up to 2GB. An integrated ISP with support for an HD camera (up to 8MP) and secondary camera (up to 2.1MP), the processor also comes with an embedded multimedia card at 4.41.

Intel claims that there's no reason that Atom based Windows 8 tablets, from a hardware bill of materials perspective, should be any more expensive than their ARM based counterparts. The important takeaway is that Intel is significantly reducing the price of the Atom Z2760 due to competitive pressure from ARM. Most ARM smartphone SoCs seem to be priced in the $15 - $30 range, and I'd expect the Z2760 to fall somewhere in that range. Intel has shipped cheap CPUs in the past, but I don't know that they've ever shipped something this cheap. ARM's impact on Intel is measurable, it is the new AMD.

So How will This Shake Out?

Exactly how this competition shapes up will depend not on performance or power consumption but on the ratio between the two: performance per watt. And that metric is fueling a fiery debate over the fundamental differences between Intel’s x86 chips and ARM’s processors.  

The Devil is in the Details

But the most obvious difference between the two may not actually be the important one, according to experts. ARM processors use reduced instruction set computing (RISC), while x86 processors rely on an older approach, retroactively dubbed complex instruction set computing (CISC).  

Both RISC and CISC architectures govern the set of machine-level instructions, compiled from more complex code, that a chip can execute. CISC chips have a wider vocabulary—they can perform certain operations in one step that might require a series of commands on a RISC chip. But RISC chips can better handle speed-boosting tricks like allowing overlapping operations during each clock cycle. 

As a result, over the years, Intel has incorporated decoders into its x86 chips to convert CISC instructions to RISC instructions to boost performance. This conversion process takes energy, but it’s unclear whether this added step gives ARM an advantage when it comes to efficiency. 

Instead, other differences between ARM and Intel chips may have more of a bearing on the coming competition. One key difference is microarchitecture—the particular way that processor resources such as cache and registers are distributed and instructions are scheduled. Today’s high-performance processors, for example, are designed so instructions can be performed out of order. Every part of a computation is done as soon as possible to boost speed. Chips that employ this approach have built-in bookkeeping to make sure that the results are assembled in the right order at the end of the process.  

Such tricks can have a big impact on efficiency and performance, says Benjamin C. Lee, an assistant professor of electrical and computer engineering at Duke University, in Durham, N.C. While a researcher at Microsoft, Lee studied how well the company’s Bing Web search engine performed on Intel’s out-of-order Xeon server chip and its in-order Atom netbook processor. Each core on the Atom chip could handle queries at half the rate of a Xeon chip core but required just 20 percent of the energy per request. However, Atom wasn’t able to handle some of the more complex requests. 

Source(s):

http://www.anandtech.com/show/6340/intel-details-atom-z2760-clovertrail-for-windows-8-tablets
http://www.notebookcheck.net/Intel-Atom-Z530-Notebook-Processor.25517.0.html
http://ark.intel.com/products/family/29035
http://www.pcmag.com/article2/0,2817,2357349,00.asp
http://www.anandtech.com/show/6420/arms-cortex-a57-and-cortex-a53-the-first-64bit-armv8-cpu-cores
http://www.pcworld.idg.com.au/article/440516/arm_introduces_64-bit_processors_phones_tablets_servers/

So “Once more unto the breach, dear friends, once more

About Rick Ricker

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