Intel Xeon E5 2665 's Advantages
Higher base frequency (2.4GHz vs 2.2GHz)
Larger L3 cache size (20MB vs 15MB)
Intel Xeon E5 2420 v2 's Advantages
Released 1 years and 6 months late
More modern manufacturing process (22nm vs 32nm)
Lower TDP (80W vs 115W)