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@CubanLegend I threw a 7700K in mine. The system wasn't stable at all under stress prior to de-lidding. De-lidding is a must imho.
I have a 7700k, no delid, but I got the K so that I could undervolt, as opposed to overvolting. I am sensitive to fluctuations in noise, so I disabled Turbo Boost (i.e. the processor always runs at 4ghz or less), set my CPU fan to fixed RPM, and got the voltage all the way down to 1.08v. This produces something perfectly stable but also with no real temp/noise spikes. You could get just about the same results and save a ton of money by tossing in a non-K and a normal motherboard, not sure if non Z series motherboards will still let you undervolt these days.
I'm really good at flipping my CPUs as new CPUs come out, and I always buy from Microcenter where they sell the i7 K for $50-$100 less than NewEgg, so I just get the best stuff that'll fit in the thermal/dimensional/sonic limits that I set for my S4.
Coffee Lake is 4w TDP higher but it sounds like due to architecture changes, it might be a bit more efficient with 1/2 core workloads (i.e. gaming).
I'm still waiting on Cryorig to put out the damn all-copper C7 they teased like a year ago! Still using the C7 heatsink with the Cryorig 140x13mm fan mounted to the S4 built-in fan bracket.