Intel Core i7-3930K vs. Intel Xeon Processor E5-2690

Hello friends, I was thinking that what difference between Max Memory Size 64 GB Max Memory Bandwidth 51.2 GB/s on both of them. Well when I was checking out Intel Core i7-3930K it was showing me 32 GB Max Memory Size and when I checked in some days ago then it was 64 GB. Well with Intel Xeon Processor E5-2690, was thinking that what I should to do with 750 GB Max Memory Size where I hardly use 51.2 GB/s Max Memory Bandwidth? So can you people please tell me about it? Thank you.

Let me tell you that Max Memory Size (64 GB) is the total RAM which memory controller hub supports and Max Memory Bandwidth (51.2 GB) specify how much data you can transfer from and to the RAM. Well bigger the bandwidth, the additional data you can transfer among memory and other devices at the same time, other than bandwidth is not linked to the quantity of RAM that the memory controller hub will support.