The main problem with the previous Mac Pro models and in fact with the first Xeon 5xxx platform was the low performance due to the bottleneck of the memory bandwidth.
It seems that the new Mac Pro do not suffer from this early adoption defect anymore, as illustrated by a benchmark assay run by Primate Labs to compare a new Mac Pro 8 cores 2.8 GHz with the previous Mac Pro 8 cores 3.0GHz.
When testing specifically the memory bandwidth, the performance gain reaches 30%, a huger value which can not be only due to higher clocked RAM module
