About a week ago I swapped my Core i7 5820K for a Core i7 6900K, and it's no secret it's a hot CPU. Currently running with at 25% overclock firstname.lastname@example.orgGHz at 1.252v, with a Phanteks PH-TC12DX air cooler. Under stress testing for several hours in OCCT it hits these temperatures, but I would like them a bit lower. I am therefore looking for a new cooling solution, but I can't decide whether to go air cooling or AIO watercooling. I have pro's and con's for both. With Air cooling the pro's are: no risk of leakage, no pump noise, easy to maintain. The con's are: on X99 platforms the 140mm large fan coolers can block memory dimms and first pcie slot, and making it extremely difficult to uninstall top graphics card. For air coolers I have looked at Phanteks PH-TC14PE and Noctua NH-D15S, since as for height they fit in my Corsair Vengeance C70 case, and they won't block my first PCIE slot (which is critical is when I run SLI). I had looked at the Cryorig R1 Ultimate also but I think I might be to tall for my case to accomdate. With AIO cooling the pro's are: easy access to memory, graphics cards, good cooling, optics (looks nice). The con's are: risk of leakage, pump noise. For AIOs I looked at Arctic Liquid Freezer 120mm, Arctic Liquid Freezer 240mm, Cryorig A40 Hybrid Liquid Cooler 240mm and Enermax Liqmax II 240mm. While I think the AIO provides easier acces to everything on the motherboard, my one big overall shadowing fear is leakage ! and it's almost enough to me drop the idea, when it concerns my main PC system. What would you choose ?