Intel Xeon E5 2660 's Advantages
Larger L3 cache size (20MB vs 10MB)
Lower TDP (95W vs 140W)
Intel Xeon E5 1603 v3 's Advantages
Released 2 years and 6 months late
Higher specification of memory (DDR4-1866 vs DDR3)
Higher base frequency (2.8GHz vs 2.2GHz)
More modern manufacturing process (22nm vs 32nm)