Xeon EC3529 's Advantages
Higher base frequency (2.133GHz vs 2GHz)
Lower TDP (65W vs 105W)
Xeon E7 2820 's Advantages
Released 1 years and 2 months late
Higher specification of memory (1333 vs 1066)
Larger L3 cache size (18MB vs 8MB)
More modern manufacturing process (32nm vs 45nm)