July 17, 2012


The Snapdragon S4 chip, based on the new Cortex A15-class Krait design, is currently the most advanced ARM processor core in the market. Along with the integrated LTE modem, the advanced design of the Krait architecture made the Snapdragon S4 very popular in US, both with manufacturers and end users.

But while the S4 is very good, it also has two big flaws. One is perhaps more marketing-related: being “just” a dual-core in a market filled with quad-core Cortex A9 chips. The second shortcoming, a real one this time, is the chip’s last-gen GPU. The Adreno 225 GPU is based on the very old Adreno 200 architecture, which is basically what Qualcomm had bought from AMD (Adreno is actually an anagram based on the word Radeon).

Qualcomm hopes to address these two issues with the upcoming APQ8084 chip, which is also known as the S4 Pro. The S4 Pro will have a quad-core CPU, clocked at 1.5 GHz when all cores are active, and at 1.7 GHz when only a single core is utilized (for single-threaded applications). If Qualcomm will actually be promoting their new chip this way, I’ll appreciate the honesty. In contrast, Nvidia promotes their Tegra 3 chips as “quad-core 1.4 GHz”, when in fact, the chip runs at that speed only in single-core mode. When maxed out,  Nvidia’s CPUs only reach 1.3 GHz or 1.2 GHz per core.

With the quad-core issue settled, Qualcomm is also finally switching to the new Adreno 320 GPU architecture. Unfortunately, we don’t know a lot about it yet, so we can’t say if the new GPU will be enough for the new S4 Pro to compete with the products that will be in the market by the end of the year.

So far, Qualcomm has tried to double GPU performance every year. If we assume that the Adreno 320 GPU will be twice as fast as the Adreno 225, I’m afraid that it will not be enough. It might beat the overclocked Mali 400 GPU in Galaxy S3, but it probably won’t stand a chance against the upcoming Mali T604 GPU, also rumored to launch sometime in the second half of this year.

It will also be interesting to see how the S4 Pro will compare to a 28nm manufactured Tegra 3+. I’m not expecting a vast improvement from Nvidia’s chips until Tegra 4 arrives, but Nvidia might surprise us. At least the Adreno 320 GPU will support the new OpenGL ES 3.0 and OpenCL 1.1 standards.

While it’s taking two steps forward, the APQ8084 chip is also taking one step backward — it won’t have an integrated LTE modem. Only the chips in the MSM series have that. This shows that integrating a LTE or 3G modem into a SoC can delay the chip’s launch. Qualcomm has decided that it’s wiser to launch the version without LTE first, so it can better compete on performance with other chips, such as the Tegra 3+, Exynos 5250 and OMAP 5, all of them supposedly arriving at the end of the year.

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