When I received this cooler as a Christmas gift, I was delighted. I had this stored away for a long time until I finally bought a new processor (2550K) and finally began to assemble it altogether. Putting on the rubber gromet looked simple, but was a bit of struggle and sometimes a pain in the a**. It took time and patience to ensure that the thing did clip onto the heatsink. I also had to purchase the Xigmatek Crossbow kit since this version did not come with the proper mounting tool for the 1155 sockets. After assembling in and installing it onto my computer, I saw a drastic change in temps as oppose to the stock cooler that I previously mounted in my computer.
This is all on stock clocks. Remember that ambient temperature play a role here and since I am in a very cool room, my results were fantastic. Overall this cooler is one fantastic cooler out there on the market. I love the fact that it came with an LED 120mm fan that illuminates a cool white/blue light when enabled, which looks cool!