For anyone building Xeon D or a single/ dual E5: SK Hynix 16GB PC4 2133P DDR4 Reg ECC DIMM HMA42GR7MFR4N TF | eBay by far the lowest I've seen for these and 8 avail so you can get a 64GB/ 128GB config easy.
DDR4 dropping is making D-1540 + 64GB configs more affordable. $30 in the last 2 months * 4 sticks = $120 cheaper which makes the motherboard, processor and RAM combo almost 10% cheaper in 2 months.it should be great if DDr3 16GB ram drop price also