Overclocking pushes the entire system to whatever max you can get to. Change a part of the system and that maximum can be lower, higher or the same.
No one can help since you have a new system so you have to repeat what you did to find the new maximum.
-> That said, XMP is a bit of hit or miss. You will find many discussions where folk discover it doesn't work. If you feel this is wrong then you complain to the makers. Here I have to go with real world findings and what I see. That is, we go with what works. If a client demands we overclock we no longer have that client. It's a tar pit where it may work today and not tomorrow and such demanders are always back at the shop next week on months later wanting it to run at the overclocked settings.
You might be able to get there with faster RAM but no one seems to warranty that.
Intel I7 5820K
Asus X-99 A / USB3.1
Corsair DIMM 16GB DDR4-3200 Kit (Got 1 Kit before now i got 2 Kits both with 2x8GB)
If i only use 1 Kit (old or new one) i can activate the xmp profile in the bios and everything works fine, i run my old Kit at 3200 MHZ several months.
If im adding more than this 16GB overclocking always fails.
Can someone help?