Samsung Exynos 7420 Advantages
Lower TDP (7W vs 9W)
Samsung Exynos 980 Advantages
Better graphics card performance FLOPS (0.2621 TFLOPS vs 0.1976 TFLOPS )
Larger memory bandwidth (34.1GB/s vs 24.8GB/s)
Higher Frequency (2200MHz vs 2100MHz)
More modern manufacturing process (8nm vs 14nm)
Released 4 years and 5 months late