Qualcomm Snapdragon 820 Advantages
Larger memory bandwidth (29.8GB/s vs 17GB/s)
Qualcomm Snapdragon 765 Advantages
Better graphics card performance FLOPS (0.576 TFLOPS vs 0.3194 TFLOPS )
Higher Frequency (2300MHz vs 2150MHz)
More modern manufacturing process (7nm vs 14nm)
Lower TDP (5W vs 11W)
Released 4 years and 1 months late