Noctua NH U14S or NH C14 or NH D15

[M4ttHardware]

Hi, I have decided to go for noctua to cool my i5 4670k but I cannot make up my mind between the NH U14S or the NH C14. Which one cools better? Are there any compatibility issues? I am hoping to get some advice from you people.

Also, should I bother getting the NH D15? Is the extra performance really worth the extra money and trouble of working around the large heat sink each time I try to upgrade my computer in the future.

 

[volcanoscout]

I'm currently using the NH-D14 on my i5-4670K and have been very happy with it. I've also used the NH-U14s and U12S on the 4670K and 4770K, without issue.
The NH-C14 is good if you don't have space for the larger heatsinks, has very few RAM clearance issues, does a better job of incidentally cooling RAM and other nearby components, but if you're going to do anything beyond mild overclocking, you're going to see temps 8-10C higher. There are several reviews available showing the comparisons, and all of them show the C14 lagging by a large margin behind its big brothers when at load. Same goes for the U12S - awesome for normal use and light overclocking, but not as good when you're going to really crank it up. The D14 and D15 have comparable performance but different fans (FLX vs PWM) and the D15 has better RAM clearance. I would recommend the U14S if you have the space for it, and the D15 if you have the space and the extra $ (although there's not that much difference in price).

They're all compatible with most boards and chipsets, either with standard setup or with included adapters. I use my D14 on a Hero VI inside a Fractal R4 - installation and removal is fast and stupid-simple, but haven't had any issues working around it either.