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Saw a couple of Zalman 7000's up cheap today (damaged packaging), and noticed that if you removed the fan from the second one, turn it upside down and solder it to the first, you would have a fantastic heatsink with very little extra airflow resistance, anyone tried it?
Even better would be a version with a hollow centre to the fan so that you could run a short heatpipe up to the centre of the second H/S.
Bit hard to follow, but if you get what I mean, I reckon it would make a fantastic HS?
What if you reversed the direction of the second fan? You should get 2x the airflow. Also, you might have a problem getting good heat transfer between the two heat sinks unless you're really really good at soldering and you take the time to solder EVERY fin
But of course if the fins were pressed like that at the factory...
P.S. - Second fan wouldn't help much.
you mean put the heatsink ontop of the other, joined at the tip of the fins?
someone when you're using your comp, notice how cool the edges of that heatsink is. i can only get mine to feel warm if i overclock much more than i normally do :stick:
Yes but if there's a very short heatpipe up the centre....
copper transfers energy faster than a heatpipe can, heatpipes are to save weight.
Soldering one on top another (in the center, not every individual fin) would be interesting...
Doesn'y anyone wonder why HSs are the size they are? Stacking them would make a bar twice as long and twice as heavy pulling on the mobo, that is 4 times as many FT/lbs thrown through those poor mounting holes in the PCB. I don't have the exact specs of an 8 layer PCB on hand, but I belive they are part of the reason HSs arn't larger.
actually the FT/lb would be decided by how tight the coolers were attached to the holes... this is often in excess of 60lbs.
All the extra weight of the coolers changes is about 1lb downforce on the CPU when the board is flat on the bench, or possibly allowing it to tilt if the board is dropped.
4 holes are better than 2, but you gotta drop the thing for them to be so.
it does?Quote:
Originally Posted by STEvil
maybe, but it has a much higher thermal resistance for moderate distances. (i would guess >1")
Oh. I figured 8 layer PCB was weaker than that, but I forgot how tight I tighten things down. It's deceptively strong.Quote:
Originally Posted by STEvil
I thought about it like that because the cooler wouldn't actually be that high, so it wouldn't be exerting much leverage, and would easily fit into any case that already took the original one.
Quote:
Originally Posted by STEvil
So why do they use heatpipes to cool laptops/high density electronics then?
Most heatpipes are made from copper, and if upright they will transfer heat much quicker than copper due to convection.
heatpipes are better than copper because of the change of state takeing place.
Mostly due to space and weight issues in the laptops. The phasechange aspect of the heatpipe only helps when it can transfer heat faster than copper, and how many heatsink manufacturers do you know that actually tell us what they put in there?
Convection can be forced also, but its very inefficient in either case. Filling the heatpipe with a liquid capable of absorbing, transfering, and releasing energy faster than copper would be more efficient since gases need to be held against copper to condense and evaporate as heatpipes need them to, not to mention density issues with liquid vs. gas... this is part of the capacity issue with using phasechange like vapochill..
In reality, heatpipes are not better than copper, because they are usually made of copper, for a reason... what they contain doesnt often do crap.
But it wouldn't be a heatsink manufacturer, I'd be buying one from a local company that makes them. Heatpipes can be much more effiecent than even a solid copper rod the same size when orientated correctly. As for laptops, if it was simply for weight issues, do you not think they would just use a hollow copper rod?
What wouldnt be?Quote:
But it wouldn't be a heatsink manufacturer
Orientation is only important when they are using a change of state of what is in them.Quote:
Heatpipes can be much more effiecent than even a solid copper rod the same size when orientated correctly
My guess would be that laptop heatpipes probably use the technology correctly, where most heatsinks you find for PC are largely bling factor.Quote:
As for laptops, if it was simply for weight issues, do you not think they would just use a hollow copper rod?
Great example is the 7700 vs. XP-120. They both match up nearly the same in terms of performance (the 7700 may be able to outperform the XP-120 even, after some work) but the Zalman does it by having more fin area and using the characteristics of copper (as well as sheer volume of copper) to do it.
My point is that if I did get round to doing this I would be using a real heatsink, not just ones for show like I suspect the XP-120 uses. (and it sounds like you're skeptical about them too)