Removable Video RAMsinks (pix)
 

Here's a sneak preview of a concept I have been tossing about in my head for some time, and that I've finally had the time to try out. Believe it or not, finding a 4mm drill bit here in singapore is not easy. Most hardware stores seem to only carry bits in imperial sizes. I needed a bit that was exactly 4mm, had to head to a specialty DIY store to get one (and pay DIY store prices for it!).

In any case, here's what I'm talking about:

http://theforumisdown.com/uploadfile.../ramsink25.jpg

It's a clip-on RAMsink. That's right, only mechanical retention. No goddamned thermal epoxies or frag tape.

http://theforumisdown.com/uploadfile.../ramsink12.jpg

As you can see this is just a proof-of-concept prototype. It's missing its fins, and it could also use being thicker. I'm currently thinking of how I can put fins into it with nothing but a drill press. I'm currently pondering two possible methods:

1) Use a jigsaw and try to carefully cut fins into it.
2) Use a drill press and try to carefull drill pins into it. (a la #Rotor)

Input?

http://theforumisdown.com/uploadfile.../ramsink34.jpg

The sink is fairly easy to clip on. Just put in position and tighten the nut. Wing-nuts may make this job even easier, at the risk of overtightening however. Since the clipping is only at one end there is more force on the outer as compared to the inner part of the ram chip. I am worried this may damage it if over-tightened. Also may lead to gaps at the inner (WTR to the card itself) end between the sink and the chip. I looked at it though, visual inspection seems to indicate good contact all the way down.

http://theforumisdown.com/uploadfile.../ramsink42.jpg

Here you can see clearly how the ramsink is built. I got the basic idea from F-clamps.

http://theforumisdown.com/uploadfile.../ramsink54.jpg

Here you can see the components. The two copper pieces obviously have not been finished yet. Like I mentioned earlier some kind of finning is required. I also think a thicker block of copper with a longer screw may be a good idea, to prevent the copper from bending due to the uneven pressure.

I obviously don't have any performance results as this is prototype was only meant to assess the feasibility of the concept. In this respect it has been a success.

What do you guys think? Comments/suggestions?

nice idea, but wont they heat up quickly and have trouble to dissapate the heat?

Like I mentioned these still lack finning. I'm also pondering making them thicker. With finning they would pretty much be like any copper ramsink out there...

Could you incorporate a spring on the bolt in between the two pieces? I would think you could even out the pressure somewhat like that.

problem i see with the clamp is that all of the pressure is on one side. i could see the blocks actually lifting off the farther side of the clamp.

Yes, but pHaestus has a good point, a spring on the bolt would help some by taking up the slack. Also, moving the screw as close as possible to the card. I would have the screw actually touching the card. A little AS2 or 3 and you would be set. You dont have to crank the hell out of the screws to get a good connection.

perhaps a spring in there on the other side of the bolt (opposite the card) would be good, instead of around the bolt. if it was around the bolt i would think that the symmetrical pressure would cancel out any possible counter pressure that you are needing.

The combination of the bolt very close to the card and the spring on the far end of the clamp would be about perfect if the spring had a high enough tension. After all, you aren't wanting enough pressure on the RAM to crack it ;)

Curious though, what's your beef with using an Arctic Alumina mix? Holds well and can be removed if done with the epoxy based version used only on a small section of each end and the non-epoxy version used in the middle.

I think someone also suggested (if you dont want to shell out the dough for AS epoxy, a 2/8 mix of superglue and AS2 <- I think it was that way.. not the other way around... but heck if i know..

I can think of one better way to do this!!! But it would require some work. Instead of having the bolt on the outside where the other end of the clamp will pull apart, have the nut on the inside to where when you turn it it actually created down pressure on the opposite end and will squeez together.

Pic of what I am saying. The red are nuts. The inside ones will tighten and press the other end of the clamp downward to create a nice even pressure on the other side.

http://www.dorrellco.com/clamp1.jpg

I will try that out if I can find sufficiently thin nuts :D Unfortunately for me, my metalwork tooks comprise a drill press and a jigsaw.

I had a similar idea. Instead of putting a spring on the opposite side, put a thin bolt with two nuts inside instead of outside it. Like that, by cranking the two nuts, you can get leverage that will force the entire setup to stay parallel. What do you think?

why not use a thin piece of copper to attach to the ram, then epoxy to this copper whatever heatsinks you want, it will cool better, look better, and be easier

Yeah, but I never listened to "keep it simple stupid". Hehe. If it were up to me, I would just glue the darn things.

Thin copper is pretty easy to bend, you of all people should be aware. I don't think you can go much thinner than the 1/4" these pieces are without risking it bending. I suppose that could be done, but at that point you might as well solder the two parts together. In any case I'd prefer if the whole was manufactured from a single piece.

but with the heatsinks on, I doubt it would bend one little bit.

Average heatsink is not that long, you'd bend at the interface point probably.

I have some 1/8" copper stock sitting right here that I use for the tops of my copper WB's. It will not bend in the short amount, but you do not have much area for fins unless you soldered some on.

Hmm? Well I'll take your word for it. I know I bent a bolt when doing some testing work. Wasn't a steel bolt though. But tt's really besides the point :D

IMHO soldering fins on is not a good idea. Unreliable thermal interface at the solder joint.

soldering can't be that bad, remember how well the themalright sk6 performs? Some heatsinks with soldered fins have performed really poorly, but the sk6 was consistantly good

You need to use silver based solder for good transfer. Also note ram does not need much extra cooling to begine with. Copper is really overkill. If you put enough pressure on 1/8" copper to bend it you will damage the memory chip!!! They are very touchy.

That's probably true too.

As for the SK6, they are produced industrially in a factory, not by an amateur on a table in his bedroom, and the former tends to produce better quality products if only for the better equipment present. :D