A real world case.
This is the graphics card of Apollo, where we changed the cooling to a passive heatsink.
The blower of the nVidia GeForce6600 was starting to freak out, so it was totally removed including the little heatsink.
Watch out : When taking off the heatsink and mounting a new, you have to be very careful not to distroy the delicate graphics chip (it cracks easily, and that will be the end of your graphics card!).
A good CPU-heatsink from an old PC was modified and mounted instead. The picture shows the heatsink with its former blower and AMD K6 cpu.
We made two threaded 3mm holes in the good old heatsink, to fit with the holes in the board.
Then the heatsink could be mounted, with screws from the back. Use isolating washers to prevent the springs from making contact with some tracks on the board.
Note that the springs from the original mounting-pins were re-used for the screws.
Important!!!!! Firstly, I used the screws as they were, but it turned out that the heatsink couldnīt settle flat on the chip because the thread of the screws prevented the screws from moving freely through the holes. So I filed off part of the thread and that made it perfect.
You should also remember to use cooling grease between the chip and the heatsink.
And also very important; you only can live with passive cooling when you have sufficient airflow in the cabinet, and this flow has to be passing the new heatsink.
It worked nicely, and the temperature of this heatsink while running full speed inside Apollo is only slightly above 35C.
The only cooling here comes from the front cabinet cooler.