Xeon W 1390 's Advantages
Released 9 years and 2 months late
Higher specification of memory (DDR4-3200 vs DDR3)
Newer PCIe version (4 vs 3)
Larger L3 cache size (16MB vs 15MB)
More modern manufacturing process (14nm vs 32nm)
Lower TDP (80W vs 130W)
Intel Xeon E5 1660 's Advantages
Higher base frequency (3.3GHz vs 2.8GHz)