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Qualcomm details Snapdragon 'Krait' improvements

Qualcomm has released a white paper detailing the improvements due in the second generation of its popular Snapdragon ARM-based system-on-chip design, and for those who've read Nvidia's work some things will seem remarkably familiar.

The broad details of the Snapdragon 'Krait' S4 series were already well known, as outlined to us by product management veep Christiano Amon at the company's Innovation Qualcomm event earlier this year: built on a 28nm process, the S4 series will include single-, dual- and quad-core parts running at speeds of up to 2.5GHz and with dual- or quad-core Adreno graphics processors.

A few days after Qualcomm's presentation, rival ARM licensee Nvidia released a white paper describing its competing Tegra 3 'Kal-El' processor, a five-core design featuring a patented technology known as 'Variable SMP,' or vSMP. Although Nvidia might hold the patent on that particular trick, Qualcomm's got something similar of its own planned for the S4 series: Asynchronous SMP, or aSMP.

It's not quite as clever as Nvidia's equivalent, however: while aSMP allows Qualcomm to adjust the clock speed and voltage of each processing core on the SoC independently, the company's design doesn't include the 'Companion Core' of Nvidia's Kal-El product - a lower-power fifth CPU core, designed to pick up the load for background tasks and which allows the main four CPUs to be completely deactivated to save power.

That's not a bad thing, claims Qualcomm, accusing its rival's five-core design of unnecessary complexity. "aSMP also eliminates the need for 'companion' or 'little' cores, since each core in an aSMP system can be operated in low power mode due to the independent voltage and frequency control per core - thus reducing the need for hypervisors or more complex software management of disparate cores," the company's white paper claims.

Despite the lack of a dedicated low-power processing core, Qualcomm claims the Snapdragon S4 series will offer major improvements over their predecessors in thermal performance. A combination of a move to a 28nm process size along with the use of ARM's latest micro-architecture improvements means a 60 per cent boost in performance over the current-generation Scorpion design and a 25-40 per cent saving in power.

The new generation of Adreno processors also promises impressive improvements: offering twice the performance of the current-generation Adreno 220 and six times that of the Adreno 200, the Adreno 225 included in the S4 series packs a unified shader architecture along with double the memory bandwidth and OpenGL ES 1.1, OpeGL ES 2.0, and DirectX 9.3 support.

That latter functionality is key for Qualcomm's plan to be one of the first companies to hit the market with ARM-based Windows 8 laptops, as explained to thinq_ by vice president Terry Yen during Computex earlier this year. There's another trick up Qualcomm's sleeve for the S4 series, however, and one which Nvidia is going to struggle to match: integrated Long Term Evolution, or LTE, modem technology.

Integration has always been Qualcomm's key selling point for its system-on-chip designs, and while Nvidia has stated that it's moving towards a more heavily integrated design for now Qualcomm still leads the way. The Snapdragon S4 looks like being no exception, with Qualcomm promising a brand-new modem design featuring support for world-wide 2G, 3G and 4G LTE mobile networks.

In addition, the first Snapdragon S4 to be launched - the MSM8960 - will include support for both GPS and GLONASS satellite navigation systems, Bluetooth 4.0, Wi-Fi 802.11a/b/g/n, FM radio, and Near-Field Communications technology. From the list, one thing is clear: Qualcomm is aiming its latest Snapdragons at companies looking to create highly connected devices including smartphones, tablets, and fully-integrated laptops.

The final key feature of Qualcomm's next-generation chipset offering is the Haxagon Digital Signal Processors. Built on a low-power 28nm process, the fourth-generation design allows offloading of audio, sensor processor, video or imaging tasks from the main CPUs using a C/C++-addressable tool chain. Whether the DSPs will offer improvements to rival Nvidia's 'Companion Core,' however, remains to be seen.

Qualcomm's white paper promises much, but there's a couple of key points missing: a firm launch date, and pricing information. With Nvidia's Tegra 3 'Kal-El' processor already popping up in tablet designs, it's going to have a get a wriggle on if it doesn't want to be beaten to market by its brash young rival.