A VGA card assembly includes a VGA card (90) having a heat-generating electronic component (94) mounted thereon and a heat dissipating device thermally connecting with the electronic component. The assembly includes a flow director (50) defining a receiving room (57) therein. A thermal module (10) is received in the receiving room. A bottom of the thermal module contacts with the heat-generating electronic component. A cover (80) is movably mounted on the flow director to cover the thermal module in the flow director. The cover is capable of rotating or sliding relative to the flow director to facilitate open or close of the receiving room. When the receiving room is opened, the thermal module is exposed.