This was most probably said,but if i put those 2x32gb cucial in the x99e-itx/ac pared with let say a e5-2690 v4 and a high end gpu shoud i be expecting some bottlenecking or decreased performance thanks to the dual channel memory?+2 ssd (its a workstation).
There are probably some tasks out there that can completely saturate the 18-20G/s bandwidth you'll get with DDR4 2133 dual channel, but nothing I can think of outside of synthetic memory benchmarks. Generally speaking, the CPU (and if you're running large datasets off the hard drive, the SSD) is going to be the bottleneck. Gaming is certainly not going to be an issue.
I plan to run mine in a SFF workstation with a 2683 v4.