Intel Xeon E5 2403 v2 's Advantages
Released 1 years and 6 months late
More modern manufacturing process (22nm vs 32nm)
Lower TDP (80W vs 95W)
Intel Xeon E5 2660 's Advantages
Higher base frequency (2.2GHz vs 1.8GHz)
Larger L3 cache size (20MB vs 10MB)