I started a thread a few days ago about a new build and I think I'm ready to start adding hardware to my cart now, but I've got to make a decision and would appreciate some feedback. I'm moving up from an old i5-2500k that's running at 4.4 w/ an  HDD and a GTX960. 

My question is, should I go with the i5-7600K or the i7-7700K (about a $100 difference today)? Obviously, if money wasn't a factor, I'd go with the 7700K, but I'm trying to save as much as possible and didn't want to splurge if the 7600K would give me similar results. I do plan on overclocking either CPU and using a water cooling (I've been using an air cooler for the last five years). I'll have to keep the GTX960 for a few more months before upgrading to a 1070. 

Also, what RAM/speed would you suggest? 

Thanks

Actually, next week end I will be building my daughters rig. With a 7600K. 

Asus Strix Z270I Mini ITX board.

The 7600K should manage 4.8 GHz. 5 GHz for some. Given that the sim doesn't benefit much from HT, I would think your results would be good. With no HT, temps should be 10 degrees lower.

My 6700K (4.6 GHz OC) rig runs with an NH-D15S air cooler. No need for an AIO at all. Only the very best AIO's with 280 rads compete with it and then not by much. No pump to fail and zero chance of leaks. My personal choice, but if you favour AIO, that's fine.

My daughters 7600K will be cooled by a Noctua NH-C14S so it will be interesting to see what sort of OC it can handle. I'll upgrade it if not suitable, maybe even to an AIO given the minimal space, but in all the tests I've seen, it's within two degrees of the D15S which is quite frankly stunning for a single heat-sink design! With the added advantage of course of blasting air down at the motherboard VRM's etc.

For my daughters rig, (mainly going to be used for games and her work, she's a data analyst) I went for GSkill Ripjaw V 3200 MHz. Great modules from GSkill. In theory Kaby lake will handle higher frequency. My board right up to a stunning 4266 MHz in theory. 3200 is fine for my daughter through and cheaper.  Depends what you can afford and your motherboards capability.