Short answer is you may need to use xmp to set the memory to that speed. What are your system specs?
Okay- here are my specs ('short' verion):
Intel Core i7 5820K (with water cooling)
Full thermaltek tower with a 900 watt power supply- I leave the side panel open to allow for better cooling, mainly of the graphics card as it tends to run hot
8 gigs DDR4 DRAM by "Crucial Technology" (1,200 MHz- it is under the water cooling system a local PC store installed for me, so I will have to remove the cooling unit somewhat to get at the RAM so can't give you more details)
ASRock X99X Killer motherboard
Drive C: internal SSD drive 120 gig
Drive D: internal SATA hard drive roughly 3 terabytes (2.73 available)
External USB 3.0 hard disk- 4.55 terabytes (almost full, encrypted with Windows 10 Bitlocker)
(due to lack of space- I mainly use drive C SSD drive for windows, my user profiles (take up a lot of space, and programs required to install to C drive. I can't backup my iPhone 7 Plus because, last I checked, iTunes requires it be on the C drive and I just lack the space. I keep my programs and games on drive D, and video files/pictures/backup stuff on the external drive)
I forget- I may have used the BIOS to overclock just slightly (I need to check), but needless to say when it comes to multi-threading my CPU-Z score (comparing it to other CPU scores) is 3617, single thread is 476. For multi-threading, that puts my I7-5820k above an Intel Core i7-6850K (3404) and just below the AMD Ryzen 5 2600X (3640) and Intel Core i7-8086K (3773).
OS: Windows 10 Professional (though it seems to be a bit screwy at times- hey, I manage)
I have the Occulus Rift and Oculus Touch, and my monitor is a Samsung large 3DTV (so, limited resolution but large screen and- hey, can watch 3D with active 3D glasses).
I am upgrading the RAM and the video card- and I am hoping that perhaps the VR game "Star Trek Bridge Crew" will finally work without crashing once I do. I am getting the above-mentioned RAM, and also upgrading to a new video card to help handle the VR and gaming/video editing/art/etc (Asus Geforce GTX 1060 6 GB ROG Strix OC edition).
Hope that helps