I have a case with one fan in back (exaust) and one in the bottom of case (intake) near front. I did not think that it was sucking in much air, so I took a pair of tin snips and cut the perforated metal out of the bottom of the case as I am sure this restricted the air flow. It helped my temps and you can hear that the fan is not struggleing to get air now.
main rig..amd 2500mobile oc@2200,ga7n400-e-l, thermaltake silent boost, audigy2zs,creative 7.1,1024 ocz performace ram, gigabyte 9600pro,2 40 and 160gig hd, ultra x-connect 500watt ps.
hp 2.8 laptop