Xeon E7520 's Advantages
Larger L3 cache size (18MB vs 6MB)
Intel Xeon E3 1278L v4 's Advantages
Released 5 years and 3 months late
Higher specification of memory (1600 vs 1333)
Newer PCIe version (3 vs 2)
Higher base frequency (2GHz vs 1.866GHz)
More modern manufacturing process (14nm vs 45nm)
Lower TDP (47W vs 95W)