Intel Xeon E5 2609 v2 's Advantages
Released 3 years and 6 months late
Newer PCIe version (3 vs 2)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (80W vs 95W)
Intel Xeon X5660 's Advantages
Higher base frequency (2.8GHz vs 2.5GHz)
Larger L3 cache size (12MB vs 10MB)