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Heat Sink Orientation - most efficient

Last response: in Overclocking
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November 20, 2008 4:37:09 PM

Hi trying to figure out what the most efficient layout might be. I have a Zerotherm Zen and I could either mount it horizontal so it blow up into the PSU (which has 120mm fan like the HS) or towards the back.

I have two 80mm high cfm fans exhausting high in the back one above the other. Up front I have two more and they are side by side very low. Two hard drives lie in front of these. I have a large video card with a full second slot cooler.

My initial thoughts are to mount it to blow up since all my air intake is very low at the bottom of the case.
November 20, 2008 4:56:26 PM

the only problem with having it blow into the psu is that you might cause some overheating issues for the psu.
November 20, 2008 5:10:12 PM

I agree with possible overheating issues on the PSU, even if you don't get the overheating, you are most likely going to cause the fan to spin up faster and therefore be noisier. (I prefer less noise, you might not care)

Also the best arrangement for these tower heatsinks is to position it so the fan blows air into the heatsink and exits to the exhaust fan(s) in the rear of case,... unless your psu is mounted at the bottom,... then it might be a different story.

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a c 330 K Overclocking
November 20, 2008 5:12:48 PM

Either way is fine, most people mount it to blow out the back. You aren't going to overheat your PSU from your CPU cooler blowing air into it...if you have that much heat coming off your CPU, or that your PSU would overheat from that air in your case anyway, you have other problems to worry about than which way the fan blows.
November 20, 2008 5:31:06 PM

Generally you are right about the PSU, depending on the situation, but it will generate more heat than previously and most likely rev up the 's rpm at the very least,... causing more noise (Some prefer silent computers, so this would make it an immediate no brainer for some)

Now say if you are pushing the OC and the temps, have a poorly ventilated PSU that is already running close to 100%,... you can theoretically overheat the psu. I will agree though if this is the situation,... you should worry about other things first!!! ;) 

Either way, the heatsink exhaust should just go directly out the back, it is most efficient, which was the question.
November 20, 2008 9:02:32 PM

Vertical it is then. I was afraid the HS might be starved of air slightly but I guess its not much of an issue
a b K Overclocking
November 21, 2008 1:53:48 AM

Its a bit late, but....Out the back in your case, you do not want the psu having to put up with hot cpu air.

If you have a case with a top fan :)  up and at them :p 
November 21, 2008 12:23:34 PM

in the heatsink articles at Xbitlabs they have mentioned to get 1-2C lower temps when the heatsinks are oriented in a such way that the heatpipes themselves are as horizontal as possible. Typically the less there is vertical difference between the hotspot (core) and any part of the pipes the better. This applys to cases where the mobo sits vertically, so most of the normal cases.

the best scenario would be if mobo is laying horizontaly and the heatsink sits on top of it vertically, ie the hotspot is at the bottom end of the pipes. so the pipes would work most efficiently.

But yeah the difference ain't that big, and it might be better just to blow the heat out of the case as fast as possible. in which ever direction that might be... :) 
November 22, 2008 12:55:02 AM

I disagree since the best scenario is a motherboard is vertical as in most towers, and the heatpipes are side to side horizontally (which would lead to heat blowing upwards), just based on this review:

http://benchmarkreviews.com/index.php?option=com_conten...

However it still depends on where the psu is mounted (top or bottom of case) since you don't want to send extra heat through the psu, if you do, you might lower your cpu temp 1-2 degrees, but you will heat up the psu temps probably by 5-10 degrees,... which in extreme situations could be bad on the psu, but will rev up the fan causing more power to be used and more noise.

If the psu is bottom mounted, yes point the exhaust at the exhaust fan at the top (if your case has one).

Now really, we are all talking about a degree or two difference and possible few dBA with psu,... there are things that will make a bigger difference overall (like an aftermarket HSF over stock, Overclocking the chip or not, case fans or not, etc)
November 22, 2008 6:46:47 AM

it depends on the orientation of the cores. duals should face upwards, quads out the back. however, in saying that, i have a dual with a top mounted cpu and a S1283, and i blow it out the back. :lol: 
November 23, 2008 3:57:08 AM

Well I've faced it out the back. Temps are sorta weird, not what I was expecting, the CPU idle is 28 C and the MB is 35 C and my 8800 is 54 C. Not used to seeing a lower CPU temp then a system temp.
November 25, 2008 2:48:20 AM

@ V3nom

I would really like to see some independent reviews that show that duals and quads should face specific ways,... never seen any that show any difference in temps,...

Also,... even if there was a slight difference,... I think if you read my replies in this post it shows that would not always be the best scenario anyways,... it depends on the case, position of psu and such too, some of which would have much more effect,... I also showed in the same case scenario that a tower laid on its side and a tower upright with heatpipe "tower style "coolers can make a difference as well,... so if there is a difference with quads and dual cores I would like to see the reviews, and see if it is just pertaining to certain types of Heatsinks,.. in the case of direct touch heatsink configurations I might be able to buy into this,.. otherwise I am not so sure,...
November 25, 2008 3:29:22 AM

lupiron proved it. that's really only with HDT coolers though... forgot to mention that :p 
a c 86 K Overclocking
November 25, 2008 9:21:50 PM

KnightSaber said:
Well I've faced it out the back. Temps are sorta weird, not what I was expecting, the CPU idle is 28 C and the MB is 35 C and my 8800 is 54 C. Not used to seeing a lower CPU temp then a system temp.


What are you using for temp measurements? Since you didn't mention individual core temps I suppose your using the Mobo software? Try using realtemp or coretemp. Also loading the CPU is where temps really matter. Try Orthos as one loading siftware, use small FFT to load the CPU, it also has a decent mem tester.

ATI Tool is nice for GPU temps, and Furmark is the most stressful for the GPU load tests right now.

Mobo temps, is that your NB? Or just the temp sensor on the chip that the Mobo uses, it's usually off. CPU core temps is where it really matters.
November 26, 2008 3:24:40 PM

Yeah its the software with the mb. I tried using other software to get core readings but I think my sensors are faulty...the temps do not change when started.
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