Intel Xeon W3690 's Advantages
Released 11 months late
Higher base frequency (3.466GHz 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 12MB)
Lower TDP (95W vs 130W)