Qualcomm offers a few scant details about the Kyro CPU in its Snapdragon 820 processor

Qualcomm's introducing its Snapdragon 820 processor using the latest and most annoying trend in tech: dribble out one small detail at a time over the span of weeks. We've already heard about the GPU/ISP and the DSP, and now Qualcomm is talking about the Kyro CPU. Unfortunately, the blog post in which it details the CPU is thin on details.

The Snapdragon 820 is said to be optimized for "heterogeneous computing," one of the latest buzzwords in CPUs. It's a fancy way of saying "the CPU is made to divide up tasks between it and specialized hardware like the GPU, DSP, or image processor instead of doing everything by itself." Without any details about exactly what is going on inside the processor, it's a fairly meaningless buzzword.

Qualcomm says it's "Symphony System Manager" makes all the various parts of the Snapdragon 820 work together for higher performance and lower power use. But mobile processors have had sophisticated hardware to manage the power and performance of CPU cores and the GPU and DSP and such for quite some time now. The company didn't go into detail about exactly how the Symphony System Manger works, and what makes it different than the similar hardware on its previous chips.

Digging through the blog post and cutting out the hype-y buzzwords, here's what we can dig out:

1. The Snapdragon 820 is made using the latest 14nm manufacturing process.

2. It has 4 custom CPU cores named Kyro (previous Qualcomm chips like the 801 and 805 used custom cores, but the 810 used ARM-designed cores). They can run up to 2.2 GHz.

3. Qualcomm claims the chip (not the CPU cores, the chip as a whole!) can offer "up to" double the performance of the Snapdragon 810 and double the power efficiency. More on that in a bit.

4. There's a sophisticated system manager called Symphony that carefully manages the power state and performance state of all the major parts of the system-on-chip (CPU cores, GPU, DSP, image processor, display engine, memory system, and so on).

Pay particular note of the "2x the performance and power efficiency" claim. Qualcomm is not stating that the Kyro CPU is twice as fast, just that the new Snapdragon 820 chip as a whole is up to twice as fast as the 810. That's an important point, because it's wholly dependent on what's being measured. Is that 3D games performance Is that the image processor Some combination of pieces working in an optimum configuration 

Similarly, double the "power efficiency" doesn't mean twice the battery life. Power efficiency means "how much work gets done in a given amount of power." If it's twice as fast and uses the same amount of power, that's double the power efficiency. It's sort of a meaningless statistic without looking at the workload involved. Also note, much of the power drain of a modern mobile device is from the display and radio, so you can cut the processor power use in half and you won't double your battery life.

The story behind the story: Qualcomm endured some bad press and lost customers over the Snapdragon 810, which was criticized for running hot and not providing enough of a performance improvement over it's previous Snapdragon 805. The company is trying to make sure everyone knows that its next big high-end chip, due to appear in phones in early 2016, will be super fast while sipping battery and running cool. And maybe it will! But the trickle of buzzword-laden information it is doling out sound like the promises of every processor maker, ever: it's faster, it's more energy efficient, it enables things you never dreamed of. We'll try not to get excited until we see some actual independent hardware tests.


Jason Cross

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