Xeon X5355 's Advantages
Higher specification of memory (DDR3
Depends on motherboard vs DDR3)
Higher base frequency (2.667GHz vs 2.1GHz)
Intel Xeon E5 2620 v2 's Advantages
Released 6 years and 10 months late
More modern manufacturing process (22nm vs 65nm)
Lower TDP (80W vs 120W)