Samsung Exynos 7420 Advantages
Larger memory bandwidth (24.8GB/s vs 14.9GB/s)
Higher Frequency (2100MHz vs 2000MHz)
Qualcomm Snapdragon 665 Advantages
Better graphics card performance FLOPS (0.2432 TFLOPS vs 0.1976 TFLOPS )
More modern manufacturing process (11nm vs 14nm)
Lower TDP (5W vs 7W)
Released 4 years late