"YOU" being the ones that did, not you personally. I meant no disrespect. And we can argue the "tell the difference" all day. I'm sure you can, point is not worth the money for 60hz and better gaming at 1440p.
Your fps dips are probably more related to the speed of the drive you are using, you have excellent throughput with the cpu and memory, but if your hard drive cant keep up with delivering the data you are going to get lag, dips, stutters etc.
Your gpu is a little warm at 76c, it could be thermal throttling even at that temp causing disruption in fps. Try cranking up your case fans to expel the gpu heat and see if you can cool it down a bit.
I'M not saying this to be mean, but you seem focused in on the speed of your monitor. Honestly you would be better off with a nicer looking picture at 1440p say at 144hz. You would get the best of both worlds. At 1440p people can not tell the difference between 1440p and 4k because they are...
Sorry I was away. Answer to your question, if you look up the memory list for your board it shows your model memory, actually the whole corsair memory line, if you buy 3000mz memory it is supported at 2933. http://prntscr.com/mx9or5