Insert the tip of a small flathead screwdriver between the X clamp and its retaining post on the heat sink.

Pry the X clamp away from its retaining post until it is lifted above the small groove cut into the retaining post.

If necessary, insert your screwdriver parallel to the motherboard between the X clamp and its retaining post. Twist the screwdriver to fully release the X clamp from its retaining post.

Repeat this process for all four corners of the X clamp.

When removing the last corner of the X clamp and holding the motherboard upside down, be sure to catch the CPU heat sink to avoid damage from it falling.

Remove the CPU heat sink from the motherboard.