Summary: Despite the very un-cool aspect (sorry for the pun) of putting a "stock" cooler on a $1K processor, this cooler is very capable and quiet. I put this on an i7-4860X (130 Watt), and with "BurnIn Test" running all cores at 100% for 10 minutes, no core got over 71C, with the average in the upper 60's. The fan never sounded like it was working hard. I'll be using it in other builds.
Summary: Sometimes simplicity is the best solution. After experimenting with a fancy and expensive water cooling solution that ultimately failed. I got this as a temporary solution. Hah! It works better than the water cooler ever did. Way, way better. I never expected comparatively small fan and heat sink to keep an i7-3930k cool. After all the water cooler struggled to keep it below 80c. Hah! My core temps never get above 60c now.
Summary: This fan/heatsink worked very well on my standard clocked 4820 CPU. I replaced it though when, during the summer, the ambient temp in the house began to rise to 26c and cpu temps began to rise to the 64c mark. One afternoon at 27c in the house, I ran prime95 as a test and shut the test down when the cpu hit 68c. I cleaned some dust off the fan blades, and the heat sink, and re-ran the test with the same result. The fan seems to have worked great for about 9 months.
Summary: I purchased this heatsink to replace a Corsair H80i which was taking up WAY too much space in an NZXT phantom case. I do not really overclock my CPU (Core i7 4930-K) as I feel it is powerful enough at the stock turbo speeds for my gaming needs. This actually allows my case to stay cooler overall than the massive H80i. For the price it cannot be beat if you are not overclocking at extreme levels.
Summary: I'm using this with a Xeon E5-2620 V2 CPU. I see no need for any more cooling than this air cooler provides. Installation can be a little tricky. The motherboard I'm using is a Supermicro X9SRA and it mounted fine. But I had to just start all four screws before turning any down. They recommend evenly turning the screws (instead of one at a time). Once the screw stops, you're done. You don't need to torque them down.