Installing a fan on videocard: should the air flow inwards or outwards the heatsink?

[Repairnewbie]

Installing a fan on videocard: should the air flow inwards or outwards the heatsink?
Which works best? pushing air inside heatsink or expelling hot air outwards?

[Cricket]

Install the fan so it blows down on the heatsink.

:) Cricket

[SpikiestDog2]

Yes, I tried it sucking off the heatsink. Doesn't cool as much. You get about 25% better coolling if it blows on it.

[blue60007]

Can't pull/intake air from inside the heatsink as it can from the open case.