Qualcomm Snapdragon 821 Advantages
Larger memory bandwidth (29.8GB/s vs 25.6GB/s)
Qualcomm Snapdragon 7 Plus Gen 2 Advantages
Better graphics card performance FLOPS (1.7817 TFLOPS vs 0.3343 TFLOPS )
Higher Frequency (2910MHz vs 2342MHz)
More modern manufacturing process (4nm vs 14nm)
Lower TDP (6W vs 11W)
Released 6 years and 7 months late