Qualcomm Snapdragon 820 Advantages
Larger memory bandwidth (29.8GB/s vs 17.07GB/s)
Higher Frequency (2150MHz vs 2000MHz)
MediaTek Dimensity 800 Advantages
Better graphics card performance FLOPS (0.3328 TFLOPS vs 0.3194 TFLOPS )
More modern manufacturing process (7nm vs 14nm)
Lower TDP (8W vs 11W)
Released 4 years and 1 months late