Xeon E7520 's Advantages
Higher specification of memory (1333 vs 3)
Larger L3 cache size (18MB vs 8MB)
Intel Xeon E3 1220L v2 's Advantages
Released 2 years and 2 months late
Newer PCIe version (3 vs 2)
Higher base frequency (2.3GHz vs 1.866GHz)
More modern manufacturing process (22nm vs 45nm)
Lower TDP (17W vs 95W)