Intel Xeon E5 2667 's Advantages
Released 2 years late
Newer PCIe version (3 vs 2)
Higher base frequency (2.9GHz vs 1.866GHz)
More modern manufacturing process (32nm vs 45nm)
Xeon E7520 's Advantages
Higher specification of memory (1333 vs 3)
Larger L3 cache size (18MB vs 15MB)
Lower TDP (95W vs 130W)