Intel Xeon E5 2665 's Advantages
Higher base frequency (2.4GHz vs 1.8GHz)
Larger L3 cache size (20MB vs 10MB)
Intel Xeon E5 2603 v2 's Advantages
Released 1 years and 6 months late
More modern manufacturing process (22nm vs 32nm)
Lower TDP (80W vs 115W)