Qualcomm Snapdragon 660 Advantages
Lower TDP (5W vs 9W)
Samsung Exynos 990 Advantages
Better graphics card performance FLOPS (1.126 TFLOPS vs 0.2176 TFLOPS )
Larger memory bandwidth (44GB/s vs 13.9GB/s)
Higher Frequency (2730MHz vs 2200MHz)
More modern manufacturing process (7nm vs 14nm)
Released 2 years and 5 months late