Qualcomm Snapdragon 801 Advantages
Higher Frequency (2500MHz vs 2000MHz)
Lower TDP (6W vs 9W)
Qualcomm Snapdragon 670 Advantages
Better graphics card performance FLOPS (0.3584 TFLOPS vs 0.148 TFLOPS )
More modern manufacturing process (10nm vs 28nm)
Released 4 years and 6 months late