Is this a bit of overkill heatsinking? :P

[Sammus]

Howdy... well I've just performed griffinru's 'stage 1' mods to my MM. I really should have just paid him to do it because soldering on that board is really a lot trickier than I thought. After nearly breaking the thing several times, I think I have fixed it, but onto the point of the thread: I picked up a nice zalman cpu northbridge heatsink that fits nicely with a bit of dremel work. Haven't attached it yet... it does seem like total overkill though , whatya think?

Yup, definately overkill..

[thorbinator]

Heh, I say there's no such thing as overkill in cooling. I have a zalman 9500 for my computer and its not overkill.

Hope you are not thinking of installing the 9500 on your RC car! hehe :)

[DrKnow65]

Yes, it is overkill. As a matter of physics you need to consider thermal conductance. Conductance is basicaly how fast the heat can move through the material (i.e. light a flame under a piece of aluminum foil with your finger on the other side, doesn't take long to get burnt. Light a flame under a piece of 1" thick aluminum and you could be there for a long time before you can even feel the heat).

<the base first, uncut portion of the sink> There is a fine balance in how thick the material you use for sinking the MM should be. Too thick and it actually stores heat (as the heat from an esc comes in waves -on throttle-coast-brakes-on throttle) too thin and it doesnt store any cooling for spikes...

<the fins> The fins are there to exchange heat from the material to the air, it has an ability to disipate a certain amount of heat in a given amount of time with a volume of air to put it in... the long fins on the sink you show would work well for ambient sinking, but would be waisted when you add a fan. Reason being is the bottom of the fin would have the heat exchanged before it traveled to the tip with a fan providing a volume of air within the sink.

You only need to sink off a small amount of watts from the MM (think watts like an electric heater) The sink castle puts on are close to ideal. Only thing to change is that the MM sink is not cross cut (like the new sidewinder and MMM's are) this doubles the surface area of the fins. I think Castle used that green sink because it could take more of a beeting (less chance of getting a broken fin out of the box, or after some hard use).

Take your sink and mill the bottom to 1/8" before the fins, then shave the fins down to about 1/2" above the cut (almost the same as the original bet a hair taller) then get a high flow fan like this http://search.digikey.com/scripts/Dk...me=259-1325-ND it puts out 3.5cfm and will do the MM right.

Or get a shorter sink off a video card :)

[Sammus]

Lol nice detailed response cheers. The original post was a big tongue in cheek, I knew it was way overkill :) I was thinking of crosscutting the original sink or cutting down the fins of this one, maybe taking the outside layer of fins off so it actually fits properly.

Also I dont have a mill, so I guess sandpaper will have to do the job. If i can be bothered, I'll finish with 1200 wet/dry then polish for optimum heat conductance :D

[DrKnow65]

hehehe can you say "too much thought into a simple question?" hehehe

Do leave it 1200 grit and don't polist though (if you were serious about polishing) reason being is 1) the arctic alumina won't hold it well polished 2) you get a bit more surface area if it's got scratces in it :)

P.S. Don't use arctic silver, it's conductive. Also I like the MK II thermal compound on the inside fet's and arctic alumina on the four corner fets. Sink stays on good, but you can get it off again later if you need to.