Give it as much space as possible for air on the intake side of the fan. A;lso be certain that you are getting enough airflow into the case so that the fan is not reduced in its effectiveness because it can't maintain its design pressure.
Cooling inside a computer case is an airflow system, not just a fan or two.
do pc fans like this work http://www.xoxide.com/uvslotcooler.html
i was thinken about overclocking a bit and figured i can do more if my vid card is cool so i was just looken at some options
heres another option http://www.xoxide.com/zazmvgaheco.html
this one is bigger but its ok cuz only use one other slot
or is there a better option to cool off ur vid card