Oversized RAMSinks - pros/cons?

goosee

goosee

goosee

Associate
Joined
25 Jan 2007
Posts
16
Hi

Would like to perform a few mods on a graphics card to add sink cooling to RAM chips and the VRMs. I have a variety of heat sinks I'd like to use and intend to cut/trim them down to size where necessary.

I can undestand the disadvantage of using a sink that's too small for the chip it cools. However, is there any real reason why a sink couldn't be larger (or even much larger) than the chip it attaches too, as long as the contact between the two is good? My basic physics would suggest cooling would improve, given the greater Mass of metal sink to draw heat away from the chip. Is this true or is there a good reason why sinks should fir chips plushly?

Any wise feedback appreciated!
 
On memory IC's power is mainly dissipated through the balls/legs of the IC's to the PCB. Some special IC's also have metalic bases on the package for increased conduction to a ground plane.

In either case blocking airflow to the PCB would knock out PCB cooling but it would increase cooling through the package, the best case would be to "only just" cover the IC with the heatsink still allowing airflow to the PCB.

With most VRM FET's this is very important, covering the whole area would increase the PCB temperature a lot. These FET's are dissipating a fair few watts via the metal tab soldered to the power/ground planes, they aren't designed to be package cooled.
 
You must log in or register to reply here.
Back
Top Bottom