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Direct Contact Overrated?

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a b K Overclocking
January 27, 2010 1:40:50 PM

From the new LGA1156 aircooling tom's article:

"Also worth mentioning is that the top four contenders in today’s comparison did not use direct-contact heat pipes, but instead relied upon copper heat spreaders to interface the integrated heat spreader of our CPU."

http://www.tomshardware.com/reviews/lga-1156-heatsink,2...

I've always had a sneaking suspision from the bowels of my thermal dynamic intuitions, that regardless of how well engineered, direct contact has less actual contact with the chip compared to heat spreaders. No amount of rationalization can overcome the need for contact to transfer heat. I've always felt that I was stupid and counldn't make a case that would go against the status quo of heatpipe contact preference, but these sort of results bolster my gut feelings. Now, I know that Tom's isn't a dedicated HSF website, and thus the conclusions drawn by this one article won't be as credible those which are more thorough and dedicated to HSF review. Regardless, I think it is worth some discussion amongst those with experience.
a b K Overclocking
January 27, 2010 2:29:55 PM

Have I spoken heresy? lol
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a b K Overclocking
January 27, 2010 4:21:34 PM

Haha...
I believe that direct contcat is the way to go, but they are going about it the wrong way. They need to have a cylindrical evaporator filled with there liquid of choice. Then they need to put the heat pipes coming off of this evaporator piece that is in direct contact with the cpu. That way there is more contact on the cpu... Ill draw up some pictures later.

It is unbelievable what they are doing... They put pieces of aluminum in between the heatpipes. If they want to stick with the current way of doing things, they need to press fit copper inbetween the heat pipes, then they need to either lapp it, or coat the bottom in silver.

Vapor heatpipes are a great way to remove heat. They are just going about it all wrong... If i only had acess to the resources they did.
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a b K Overclocking
January 27, 2010 5:36:28 PM

I am not surprised by the results. As usual results will vary. That is pretty much guaranteed.

When I read the article it dawned on me I always installed cpu heatsinks without direct heatpipe contact. Instead I always used heatsinks with heatspreaders. I never gave it any thought.

It might be worth going over to frostytech.com and taking a look at the cpu heatsinks in their top ten lists:

http://www.frostytech.com/top5heatsinks.cfm
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a b K Overclocking
January 27, 2010 7:35:19 PM

overshocked said:
It is unbelievable what they are doing... They put pieces of aluminum in between the heatpipes. If they want to stick with the current way of doing things, they need to press fit copper inbetween the heat pipes, then they need to either lapp it, or coat the bottom in silver.


Would not pressed fitted copper between the heatpipes be similar to a copper heatspreader that is encasing the heatpipes? It seems to me, that allowing the heatpipes to extract heat from the entire spreader which encases it, would allow more surface of the heatpipes to be exposed to heat, as opposed to the direct contact of a single flattened side, as you said, with aluminum between the pipes? Does the extra copper between the heatpipe and the CPU, even in it's thinnest quantity, as desired by the makers I am sure to save on copper used in manufacturing, really inhibit the transfer of heat so great as to trade in heatpipe surface exposure for direct contact? Does heat syphon like a liquid, and the reduced contact actually channels more heat away from the CPU via a type of heat movement pressure? Is my understanding of entropic variance far surpassed by my curiosity and ability to comprehend?
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a b K Overclocking
January 27, 2010 7:38:54 PM

With a little bit of research, I realize that heat spreaders rarely encase the heatpipes, which are pressed up against the spreader in a way similar to direct touch contacts with the CPU. Hmm.
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a b K Overclocking
January 27, 2010 7:42:01 PM

I took a quick look at the top heatsinks at frostytech.com. It's a mixed bag but direct heatpipes seem to be more common than a standard heatspreader.

All of the tower style heatsinks are variations of the original Thermalright 120. The different companies keep trying to outdo each other. I'm fairly certain we have reached the upper limits of air cooling. In That may be all we need since cpu's are becoming more energy efficient and are starting to require less power. We're seeing the same thing with video cards.

BTW - I still have my original Thermalright Ultra 120 in my emergency backup system. It can hold it's own against the competition.
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