XMP profile question

sz0ty0l4

Distinguished
Hi!
I'm a bit starter, this is the first pc i've built so far, and i've some questions.
First of all the components:

asus z97-k
i7-4790 @ 3.6 ghz
hyperx 8gb genesis ddr3 1866mhz cl10 KHX18C10/8
WD Green 2TB 5400rpm 64mb
COOLERMASTER RC-650L-KKN1 Silencio 650 Pure
Gigabyte gtx 980 wf3
FSP Raider 650
SCYTHE Mugen MAX

So i had a problem since the pc is ready because in some games gpu usage was dropping significanlty like from 99% to 0, then back, this caused fps drops freezes etc.. and i've read that it could be because of XMP profile is disabled( i don't even know what XMP profile is) . So i went to UEFI BIOS and noticed that my is disabled aswell...

There are 3 possible options in my bios :
- disabled
- XMP: DDR3-1600 9-9-9-27 -1.50v -1.20v
- XMP: DDR3-1867 10-11-10-30-2N-1.50v-1.30v

So because i thought my ram is 1866mhz i choosed the
XMP: DDR3-1867 10-11-10-30-2N-1.50v-1.30v
But i don't know what are these numbers or if it will improve anything , and i'm not even sure if i can damage my pc with this. Please if someone has enough patience try to explain this to me, or at least tell me which option to choose to get maximum performance in all games, but not damageing my pc. Thank you very much!