A heat dissipation device includes a seat, a fin set arranged on the seat,
a fan, a fan mounting device having the fan mounted thereto, and a cover
covering the fin set. The fan has a portion thereof located above the fin
set. An opening is defined in fan mounting device and communicates the
fan with the fin set and the fan with a space above a top of the fin set.
The cover has a rearwards expanding port for guiding an airflow generated
by a system fan to flow through the fin set. A top wall of the cover has
a void to expose a portion of the top of the fin set.