Pros: Outstanding cooling, very quiet with stock fan
Cons: Requires mobo removal to install
The Hyper 612 PWM has brought down CPU temps by ~5 C with lower speeds for CPU and case fans. While I still have 2 of the 120x38mm fans running on the case, I have been able to lower their speed profiles. The sound level of the PWM fan is still lost in the noise of the case and GPU fans, even if I crank up the CPU fan to full speed. The CPU temps are much improved, and the Arctic Silver 5 has not had time to break in fully.
My only complaint is that in my old case, without a cutout behind the mobo, I had to remove the board to attach the Hyper 612. I had hoped that the same mounting would be used as that on the Hyper 212. While the back plates for the coolers are identical, the way they are used is not. The 212 had studs attached with nuts on the back, which were top threaded for the heatsink bolts to screw into. With the 612, the studs are dispensed with and the mounting bolts themselves have to be fastened with nuts on the back of the board. I guess this would not be a problem if you have a cutout in the back plate of your case behind the CPU socket.
Having to remove the board is my reason for taking off a half point. Overall, I would only caution that this heatsink is massive, both in weight and in volume required to accommodate it. As with the 212, I changed the fan from push to pull because in the stock setup it crowds the RAM. The 612 fins are both thicker and wider than the 212. For those who want the cooler in updraft position instead of front-to-back, a different pair of mounting brackets is provided.
I can't comment on installation in an Intel environment. The Hyper 612 PWM is an outstanding performer once you get past installation. As mentioned, not everyone will have this problem especially in newer cases.