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Zalman 7700... Cu or AlCu?

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February 10, 2005 11:01:06 PM

Basically, which would be best? Systems I've built in the past have had two chronic problems... 1) heat and 2) noise. So in looking for a CPU fan, I've pretty much decided on the Zalman 7700. I read the review here: http://www6.tomshardware.com/cpu/20041213/index.html but from that couldn't draw a conculsion about whether to get the Cu or the AlCu. From what the testing shows, the Cu seems to perform just barely better than the AlCu and it's slightly noisier.

The main thing I noticed was the weight! Almost 2 lbs?! Wow. So I guess my question is, should the weight steer me toward the AlCu? It's going to be a tower system, so it won't be resting flat, however it will probably move only if I'm moving into a new home. I wouldn't transport it for LAN parties or anything like that.

Opinions?

<P ID="edit"><FONT SIZE=-1><EM>Edited by drake000 on 02/10/05 08:38 PM.</EM></FONT></P>

More about : zalman 7700 alcu

February 10, 2005 11:21:56 PM

Some people think that AlCu highbrid heatsinks are actually better, the thing is that Aluminium cannot transfer heat away from your CPU as fast as copper but it CAN hold more heat energy. Copper is very effective at transferring heat but if that heat is not removed quickly it will get hotter than aluminium faster.
a b K Overclocking
February 11, 2005 2:38:52 AM

Given the performance difference I can't see a good reason to use the all-copper version, ever.

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February 11, 2005 11:01:00 AM

Like Jammy said.
I think that a combination of Al and Cu works better, at least on paper. Because you will have the Cu as the base, which will transfer the heat quickly to the Al, which can lose heat quicker than Cu. Because the Zalman's have low speed fans on them you should get a AlCu one, if you would have a high airflow fan on it, I think you should take a Cu one.

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February 11, 2005 2:53:12 PM

well i had a chance to use both the aluminum and copper 7000 series althought it was notisably hevier I think there was a good 3-6 degree temp differece throughtout different parts of the day
Go with the all copper



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February 11, 2005 5:07:40 PM

I talked to some of the Physics and chemistry Grad students about this, and they all seemed to think that in theory that the copper would be more effecient but only if it had more air blowing across it so that the the heat didnt have the chance to build up. Some of them thought that the best soloution would be to have the regular heatsink fan going and to also have a fan positioned so that it met the air flow of the heatsink fan at right angles. in other words blew through the heatsink from one side to another.

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February 11, 2005 9:38:47 PM

Cooper is all around a better matterial than aluminum, except for its weight. Matterials that gain heat quicker also lose heat quicker, anyone who says differnt needs to crack open a physics book.

Thermal resistance works the same way in both directions!

Heat a brick and a cooper heatsink in the oven, then place them somewhere to cool. The brick will take longer to heat up and it will stay hot much longer.

My experiences with the 7000 series indicate that the AlCu works just as good as the Cu. Its probably very important for the base to be copper, but at the fins the Aluminum Fins seems to do as good a job as the Copper Fins.

Whatever rate heat is transfered to the air it is an order of magnitude lower than the rate within the metal. I am guessing the internal thermal resistance of the metal isn't the bottle neck.

I would look for some reviews, and if I could find any just get the AlCU since it is lighter and cheaper.


---
Err, let me backpeddle a bit. If CU is all arround better assuming a constant CPU Temp, after all the every calorie of heat needs to be eventually removed from the heatsink.

But if the CPU temp rose and fell erattically, then the higher heat capacity of the AL would tend to level out the temperature peeks.



<P ID="edit"><FONT SIZE=-1><EM>Edited by Codesmith on 02/12/05 12:03 PM.</EM></FONT></P>
February 12, 2005 12:19:53 AM

What u really want is a copper base to transfer the heat away from the CPU then an aluminium heatsink to absorb the heat while it is taken away via convection.
February 13, 2005 7:10:50 AM

I did some reasearch.

When messured by weight, Aluminum is actually better conductor of heat than copper!

It makes sense to have a copper nearer the CPU where the area of the cross section creates a real heat bottleneck, then switch to aluminum toward the fins to reduce the over all wieght.

So if you are trying to designe the best cooler under a particular weight an AlCu combo makes since.

If you couldn't care less about weight all CU coolers win.

I still like the AlCU due to its lighter weight. :) <P ID="edit"><FONT SIZE=-1><EM>Edited by Codesmith on 02/13/05 04:30 AM.</EM></FONT></P>
February 14, 2005 8:15:44 PM

is ALCU cheaper than the CU one? i think it is
February 16, 2005 11:55:54 AM

Well it does kinda make sence. Copper cannot store as much heat energy as aluminium. This means that the copper will get hotter than aluminium a lot faster, the closer somthing gets to the temperature of the thing heating it the slower heat will be transfered to it. Therefor as the copper gets hotter it actually becomes a worse conductor of heat. Now if you havnt got a fan that can cool down the copper sufficiently then it becomes a worse conductor of heat than aluminium.
February 16, 2005 9:13:01 PM

No thats BS.

The goal of a heatsink is to transfer heat not store it.

Ignoring that,

The CPU and the area of the heatsink it touches starts off at the same temperature and they remain in thermal equilibrium.
February 16, 2005 9:53:00 PM

Since they are about the same in heat dissipation, you may consider only the weight of the thing.

One of the Zalman requirements is a mainboard that CAN support its weight. So check that your mobo can take a heat sync that heavy.

Check here to see if your scan:
http://www.zalmanusa.com/usa/product/view.asp?idx=145&c...
!