Intel Xeon E5 4640 's Advantages
Higher base frequency (2.4GHz vs 2.2GHz)
Lower TDP (95W vs 105W)
Intel Xeon E5 2658A v3 's Advantages
Released 2 years and 8 months late
Higher specification of memory (DDR4-2133 vs DDR3)
Larger L3 cache size (30MB vs 20MB)
More modern manufacturing process (22nm vs 32nm)