Qualcomm Snapdragon 821 Advantages
Better graphics card performance FLOPS (0.3343 TFLOPS vs 0.2496 TFLOPS )
Larger memory bandwidth (29.8GB/s vs 26.82GB/s)
Higher Frequency (2342MHz vs 2300MHz)
Released 9 months late
Samsung Exynos 8890 Advantages
Lower TDP (5W vs 11W)