Most chipsets on the motherboard are encapsulated in a plastic sheath,
while processors are almost always covered by a metal plate that protects
the core. Such solution is used by the manufacturers to have a larger
surface to install the heatsink, facilitating the installation and minimizing
the risk of damaging the chip.
on the one side this protection is optimum to prevent irreparable damages
during the heatsink installation, on the other side it considerably
increases the heat transmission resistance. For this reason, several
expert users prefer using chips without such protection and applying the
heatsink directly on the core surface.
Browsing through the forums it is common to find users that have broken
the core of their processor while they where installing the cooling
system. This happens because the core surface is much smaller than the
heatsink base and an uneven pressure while installing is sufficient to
make the heatsink weight relieve on the chip edge only, thus breaking it.
The core protective rubbers are especially designed to ensure even
pressure during the installation of the cooling system and perfect contact
between the heat sink base and the core surface. In fact, during the
installation of the heatsink, the weight is first relieved on the rubber
only and when an even pressure is reached, sufficient for compressing the
rubber by about half its initial volume, the heatsink base touches the
core. In this way, the rubbers act as shock absorbers and eliminate the
risk of chipping and breaking the processor or the chipset.