Our NM-ISW1 shim washers that are included with the NH-D15 G2 have been introduced to reduce ILM pressure and CPU deformation on LGA1700 and must only be used on this platform. The LGA1851 socket uses taller screw heads than the LGA1700 socket, so putting washers underneath may result in the screw heads being higher than the CPU IHS, which would cause the heatsink not to make contact with the CPU at all.

Most LGA1851 motherboards with Z890 chipset come with the new RL-ILM that significantly reduces ILM pressure and CPU warp, so further reducing ILM pressure with washers is no longer helpful and may result in poor electrical contact between the CPU pads and socket pins, which can cause damage to both components.