Summary: Installed this on an ASRock Pro4 mATX 1150 board using an Intel i3-4150 processor. Even after ensuring posts were rotated opposite the arrow (just like the intel cooler) and pressing till seated, the cooler never seemed to fasten snug to the processor.
Pros: Well constructed (except for plastic mounting post inserts). Fairly quiet except when fans ramp up to max.
Cons: Retainers do not snug cooler to processor well so carefully monitor CPU temps after installing..
Summary: I bought this to replace an aging heat sink/fan on an old LGA 775 Pentium 4. I replaced it because the cooler I originally installed was beyond the point of cleaning and it had also been in use for the better part of 8 years and got pretty loud.
Summary: Set the anchors to the locked position. Place cooler, line up anchors in holes. Check your using the right holes. 1155 or 775 etc. Double check it . Hold the metal bracket of cooler tight to Main board. Push the top of anchor in the locked position, down. Then diagonally the same to each anchor.
Pros: Works well. 25C at idle, i5 2500 Good price 95 W rated