The past year has been challenging for Qualcomm. Putting four Cortex-A57 CPUs onto TSMC's 20nm HKMG planar process was not a winning combination for its stopgap Snapdragon 810 product. It was plagued by overheating issues early, likely costing Qualcomm design wins, and while improvements came in a later revision, the 810 never lived up to its performance expectations. Fortunately for Qualcomm and its OEM partners, salvation appears to be at hand courtesy of Kryo and FinFET.
Snapdragon 820 brings tangible gains to all functional blocks: CPU, GPU, ISP, DSP, and modem. We’ve been waiting awhile for the first piece of this puzzle, but Kryo, Qualcomm’s first custom-designed 64-bit CPU, is finally here. It’s architecture is clearly unique: It simultaneously resembles both ARM’s Cortex-A57 and Apple’s Typhoon CPUs. Single-core integer performance is slightly better than A57/A72, while Kryo’s floating-point performance offers bigger gains over the A57. After factoring in the A72’s floating-point enhancements, Kryo should still see an IPC advantage, ensuring it will be competitive within the Android market. Apple’s Twister CPU in the A9 retains the single-core performance crown, however, beating Kryo in both integer and floating-point workloads.
Qualcomm’s Adreno GPUs have always had strong ALU performance, giving them the edge in games that make liberal use of pixel shaders. The Adreno 530 GPU in Snapdragon 820 continues this trend, improving ALU performance even further. The 530 is no one-trick pony, though. Improvements have been made throughout the rendering pipeline, especially to vertex processing, making the Adreno 530 a more balanced GPU.
Snapdragon 820’s memory controller is also vastly improved, offering the highest memory bandwidth we’ve seen for sequential access patterns. Like the Snapdragon 808 and 810 before it, the 820’s memory system is optimized for moving around large, contiguous chunks of data, perfect for feeding high-resolution textures to the GPU or streaming pictures and video to the enhanced ISP and DSP blocks.
This preliminary look at the Snapdragon 820 did not find any weak points in its performance. While thermal and battery life assessments will have to wait until we get shipping products into our lab, the use of Samsung’s proven 14nm FinFET process helps allay fears of a Snapdragon 810 redux. Architecturally, the 820 seems to be set up well for Qualcomm’s heterogeneous computing vision.