Intel Xeon E3 1220 v3 's Advantages
Released 3 years and 3 months late
Higher specification of memory (DDR3-1600 vs DDR3)
Newer PCIe version (3 vs 2)
Higher base frequency (3.1GHz vs 2.8GHz)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (80W vs 95W)
Intel Xeon X5660 's Advantages
Larger L3 cache size (12MB vs 8MB)