the slot 75 to engage with a screw nut 87 thus the second heat sink 80 is slidably mounted to the mounting board 70 and pivotable relative to the first heat sink 10 about the axis of the through hole 38 of the first heat sink 10 a wall bounding the mounting hole 42 of the clip 40 is snappingly clipped in the groove 26 of the base 20 of the first heat sink 10 the fixing board 60 is attached to a bottom of the motherboard 6 and the connecting part 24 of the heat sink 10 is placed upon the cpu of the motherboard 6 four holes are defined through the motherboard 6 around the cpu the screws 48 of the clip 40 are inserted through the corresponding holes of the motherboard 6 and engaged in the corresponding locking holes 62 of the fixing board 60 thus the heat dissipation assembly is mounted to the motherboard 6 referring also to fig5 in use the clip 40 and the fixing board 60 are mounted to the motherboard 6 that is mounted to a sidewall of a host computer 2 and sandwich the motherboard 6 therebetween with the second finned part of the second heat sink 80 aligning with a system fan 4 that is mounted to a rear wall of the host computer 2 when a distance between the system fan 4 and the.