GSkill either Trident Z or Ripjaw V 3200 mhz 8x8 14-14-14-34 or 16x4 14-14-14-34
both use Samsung B-die memory chips and have been the best memory kits I have ever used on either X-99 or Z-170
If you are sure you will not be adding more modules than ASUS T-Toplology handles all memory slots filled with higher bandwidth than half the slots filled, if you fill all memory slots you will not be able to lower timings as much and may need a little higher memory voltage a VCSSA voltage
My personal experience, everyone else may have a different experience but these modules have worked with XMP settings on my RVE, RVE-10, MVVIII Formula, MVIII Extreme
I have been able to easily clock them to 3400 MHZ 14-14-14-32-2T with a 6950 BW-E, 3200 with 13-13-13-28 on 5960, 3600 MHZ 16-16-16-32-2T/1T with a 6700K
This has been my personal experience and I cannot guarantee everyone will have the same experience but if you search the net you will find similar results from other users