Intel Xeon E5 1660 's Advantages
Higher base frequency (3.3GHz vs 2.5GHz)
Larger L3 cache size (15MB vs 10MB)
Intel Xeon E5 2609 v2 's Advantages
Released 1 years and 6 months late
More modern manufacturing process (22nm vs 32nm)
Lower TDP (80W vs 130W)