Intel Xeon E3 1285 v6 's Advantages
Released 7 years and 5 months late
Newer PCIe version (3 vs 2)
Higher base frequency (4.1GHz vs 1.866GHz)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (79W vs 95W)
Xeon E7520 's Advantages
Higher specification of memory (1333 vs 4)
Larger L3 cache size (18MB vs 8MB)