Intel Xeon E5 2420 's Advantages
Lower TDP (95W vs 105W)
Intel Xeon E5 2658A v3 's Advantages
Released 2 years and 8 months late
Higher specification of memory (2133 vs 3)
Higher base frequency (2.2GHz vs 1.9GHz)
Larger L3 cache size (30MB vs 15MB)
More modern manufacturing process (22nm vs 32nm)