The Snapdragon 821 System on a Chip, or SoC, is a powerful and highly integrated chip that is set to power a large number of smartphone and tablet designs in 2016 and 2017. It is the successor to the Snapdragon 820, and was also unofficially known as Snapdragon 823 before Qualcomm settled definitively for the “821” name. The Snapdragon 821 will not replace the 820, but supplement it as a higher-tier option for OEMs.
As its name indicates, Snapdragon 821 is an evolution of the Snapdragon 820. It uses the same architecture, and has been optimized by the Qualcomm Architects to squeeze for performance and efficiency out of the 820 architecture. In semiconductor industry lingo, we would call this a “performance kicker” which possibly represents the most optimal implementation of the 82x Architecture before Qualcomm moves onto the next one.
Note that Snapdragon 821 is the commercial name of the product, and “MSM8996 Pro” is the internal codename. Sometimes, the same commercial name can be associated with several internal code names which are revisions, or slight variations of the same product.
One of the reasons why Snapdragon is a bit faster is because its two “performance” CPU cores top speed tops 2.4 GHz, versus 2.2 GHz for the Snapdragon 820. The two “low-power” CPU cores can now reach 2 GHz, from 1.6 GHz previously.
The graphics processor (GPU) retains the same architecture and Adreno 530 codename, but the frequency is seeing a slight bump from 624 MHz to 653 MHz. It will have some impact on performance, and should show up in benchmarks, but perceptually, it remains similar to what Snapdragon 820 is.
The more interesting point is that Snapdragon 821 is “Google DayDream ready”, and that could mean a world of difference for VR enthusiasts who want to benefit from a largely better user interface and VR experience offered by DayDream and DayDream View headset (see our Google IO DayDream VR coverage here) versus Google Cardboard and other VR interfaces and markets on mobile. When the Pixel and Pixel HD start shipping, the Nexus 6P will no longer be the only phone able to run DayDream.
DayDream compatibility does however not affect the performance of 3D applications in general, but we consider it as a major step to removing VR user interface friction on Android.
The Snapdragon 821 processor is mostly a “performance kicker” of the Snapdragon 820, which introduced most of the new features. The extra speed comes from improvements and optimizations in the micro-architecture. This is a common way to offer an extra premium tiers of chips, as many of the optimizations need time to be figured out and worked on, so it’s impossible to do it in a timely fashion with the first-generation of product (820). The Snapdragon 821 will exist alongside the 820, which will continue to ship to OEMs worldwide.