Xeon E7 4870 's Advantages
Higher base frequency (2.4GHz vs 1.8GHz)
Lower TDP (130W vs 225W)
Xeon 6756E 's Advantages
Released 13 years and 2 months late
Higher specification of memory (6400 vs 1333)
Larger L3 cache size (96MB vs 30MB)
More modern manufacturing process (5nm vs 32nm)