Samsung Exynos 7420 Advantages
Better graphics card performance FLOPS (0.1976 TFLOPS vs 0.0918 TFLOPS )
Larger memory bandwidth (24.8GB/s vs 11.9GB/s)
Lower TDP (7W vs 9W)
Samsung Exynos 9609 Advantages
Higher Frequency (2200MHz vs 2100MHz)
More modern manufacturing process (10nm vs 14nm)
Released 4 years and 1 months late