MediaTek Dimensity 800 Advantages
More modern manufacturing process (7nm vs 14nm)
Lower TDP (8W vs 11W)
Released 3 years and 4 months late
Qualcomm Snapdragon 821 Advantages
Better graphics card performance FLOPS (0.3343 TFLOPS vs 0.3328 TFLOPS )
Larger memory bandwidth (29.8GB/s vs 17.07GB/s)
Higher Frequency (2342MHz vs 2000MHz)