The i5 would be pretty future proof I guess. I hear there's an i9? or something right around the corner. When I was going to build a new computer the Devils Canyon CPU was out. I waited and all of a sudden Skylake came out. Now it's Kaby Lake. So you can't keep up. I just built my new computer on the 6th which is just an i5 6600k. It's nice I guess. Loads FSX in nothing flat considering I have so much aircraft AI. I do plan on overclocking as soon as I get my new RAM next month. So on the subject of OCing, you could do it, just make sure you don't bump the voltage too high. In fact, you shouldn't have to touch the voltage unless your OC is too unstable. I'd look at the overclock.net forum. There are many experienced users that OC.