Assistance please!, Cpu ,motherboard and Ram

[SkyBlade9000]

okay so i'm a newbie at building a computer and i'm on the stage of getting RAM

How does one know what his limit is in mhz(eg. 1333,1600,2666)

Cause i'm gonna have a i7 4790k and it says it goes up to 1600mh, yet some people says they have 2666mh ram on it and im quite confused on the limit i can go up to. Plus my motherboard says it supports ddr3 3300(OC)memory.

 

[dottorrent]

It's fine. No matter which RAM you have, it'll work fine. If you want those speeds, go into the motherboard BIOS and enable XMP Profiling to get the maximum speed of your RAM.