Creating the Most Efficient / Quiet Air Cooling

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Cod
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Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Sat Jan 12, 2013 11:59 pm

I need some help from the cooling and silence gurus. Here is my current airflow setup:

Image

The green arrows represent air coming in and yellow arrows is air leaving. The problem is, my PC sits in a TV stand with very little space around the edges. As depicted, there are 2-inches on each side, 3-inches to the rear, and 1.5-inches above. The 120mm fans are Scythe 120mm (SY1225SL12LM-P) for quiet, efficient cooling. There are two 80mm exhaust grates and a single "air" grate in the top-rear of the case, so air escapes through it as well (not shown in image). Last, I'm using the Intel stock cooler (NH-L12 ordered this morning) and the stock fans on the MSI R7850. I should mention the TV stand has a 4cm hole centered behind the PC for all the wires.

My problem is keeping the system cool after an hour or so of gaming. The temps aren't out of control, but as my gaming session goes on, the system gets louder and louder in order to keep the load temps down. Temps at stock are around 64C (CPU) and 70C (GPU). The ambient temp is around 26C (live in Hawaii). I plan on OC'ing in the future, but want to get all the stock temps a little lower first and ensure the overall cooling is efficient (especially around the GPU). The other issue I'm having is getting the hot air of of the TV stand (or at least off the bottom shelf).

Is there any way to make the cooling more efficient while maintaining a certain level of silence? Would adding a single 80mm exhaust fan in the rear help? Would a PCI slot cooler help? Regardless, I HAVE to ensure the system is rather quiet since my wife and kids use it to stream stuff.

Sorry for the long post. Any help is greatly appreciated.

Ralf Hutter
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Ralf Hutter » Sun Jan 13, 2013 7:07 am

Can you cut a hole (80mm, 92mm, 120mm etc) in the back of the TV stand and install a 12v quiet computer fan there to help exhaust the air from the cabinet itself?

CA_Steve
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by CA_Steve » Sun Jan 13, 2013 9:17 am

Yeah, you need to vent the TV stand. I'd make a hole for a 140mm fan and instead of mounting a fan, just turn the PCs rear case fan around and align it with the TV stand's new hole. If this works, then you are done. If you need more cooling, then you can add a slow 140mm fan.

A caveat: I had a failed experiment along these lines where my A/V gear was overheating in the closed cabinet below the TV. Aha! I'd make a hole for a 120mm case fan, soft mount it, use an old mobile phone charger to power the fan and plug the charger into the A/V receiver's switched outlet. It turns out the slatted wood back of my cabinet was a great amplifier for fan vibration. The next stage was to find/make a fan bracket where the bracket would be mounted to the solid/thick wood shelf and the fan would face the hole but not touch it. Never got to stage 2. :)

Cod
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Sun Jan 13, 2013 12:20 pm

There are two problems I will run into trying to cut a hole in the back of the TV stand: even the back is solid wood and my wife. Not sure how we'll she'd take to me cutting a hole in her TV stand (doesn't matter if it won't be seen).

Right now, all the exhaust locations in the rear are just grate holes. Would I benefit from putting at least 1 x 80mm fan back there to "speed up" the exhausting? I realize it would push the air out of the case faster, and if I'm correct, it would also help dissipate the heat to the top of the TV stand (up and over the cable box) quicker.

So I guess my question is, should I stick with the 80mm fan holes or actually install a 80mm exhaust fan?

CA_Steve
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by CA_Steve » Sun Jan 13, 2013 12:51 pm

Ah - I mis-read your diagram and took the BACK to be the TOP. :)

You need to have some fanned exhaust. Adding slow 80mm fans to the rear would help. Before you purchace, try experimenting with reversing the left side fan for a right to left airflow and see if temps/rpms drop.

So, the heat outside the case doesn't have anywhere to go? This is a completely enclosed 5 or 6 sided box?

Also, you can change the GPU fan profile. 70C is pretty conservative. 80-85C is fine for gaming. If you don't see artifacts or throttling, it'll be ok.

Cod
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Sun Jan 13, 2013 2:53 pm

The case is enclosed completely by the TV stand, except in the front. The front is completely open (no doors or anything). Also, the two shelves above the case aren't as long as the bottom shelf, so air can float up in the rear of the stand. I was looking at the Nexus Real Silent Case Fan (http://www.newegg.com/Product/Product.a ... 6835610004); however, I do not have any more motherboard fan headers. So it would have to be connected to the PSU. So I may have to look into a PCI fan controller as well.

I may try your suggestion later today regarding the single fan and make it an exhaust. There are no components over there, except the power supply towards the rear. The SSD is mounted above the power supply.

I know 70C is rather conservative, but I have always been very cautious with my GPUs. I will toy with the fan speeds in Afterburner to see what kind of temp and sound results I can get. Hopefully I can find a happy medium.

Thanks for the help.

CA_Steve
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by CA_Steve » Sun Jan 13, 2013 3:40 pm

If you end up adding more fans, there are splitter cables available for 3 and 4 pin headers. You could double up the fans per mobo header.

Cod
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Sun Jan 13, 2013 5:03 pm

CA_Steve wrote:If you end up adding more fans, there are splitter cables available for 3 and 4 pin headers. You could double up the fans per mobo header.
Would that split the voltage? I don't want to put too much voltage on a header and fry it.

CA_Steve
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by CA_Steve » Sun Jan 13, 2013 7:59 pm

Cod wrote:Would that split the voltage?
No. Both fans see the same voltage/PWM signal. It doubles the current draw on the fan header...which shouldn't be an issue.

efahl
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by efahl » Mon Jan 14, 2013 8:39 am

Is remixing a problem? In your diagram, the upper right corner looks to me like you could be recirculating hot air back from the exhausts into the top fan. How about getting some 2-3" blocks of foam a foot or two long and blocking the flow between the exhausts and intakes to see if that reduces the in-case temps? (Might do nothing, but it's cheap and easy...)

Cod
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Tue Jan 15, 2013 2:31 pm

efahl wrote:Is remixing a problem? In your diagram, the upper right corner looks to me like you could be recirculating hot air back from the exhausts into the top fan. How about getting some 2-3" blocks of foam a foot or two long and blocking the flow between the exhausts and intakes to see if that reduces the in-case temps? (Might do nothing, but it's cheap and easy...)
I'm not entirely sure there is any problem; however, I'm planning to OC a little in the coming weeks, so I want to make sure the cooling is as efficient as possible first. My current temps are decent in my mind (ambient temp 26C):

CPU: ~35C idle / ~65C load
GPU: ~30C idle / ~72C load

The problem comes up after I've been playing "heavy" games, such as Skyrim and Metro 2033, for longer than a hour. The temps get a little higher at that point (nothing extreme). So my initial thoughts are exhaust and/or re-circulation of warm air.

Thanks for the foam idea though. I may try cardboard first since I have some lying around.

Hopefully I can run some different test tonight as I was unable to the past few days.

Cod
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Wed Jan 16, 2013 12:25 pm

After doing some testing last night, it turns out using a piece of cardboard on each side of the case lowered temps by 2-degrees. Using the left side fan as an exhaust made no difference during the tests.

I ran Intel Burn Test for 5 runs on maximum settings. The highest recorded temp before the cardboard was 81C. After cutting and placing cardboard "blocks to keep warm air back, the highest temp recorded was 79C. I feel like 79C under maximum IBT with a stock Intel cooler is very respectable. I'm hoping the NH-L12 will lower temps even more. If I can keep max temps below 75C w/ air cooling, I will be very happy...especially if I can maintain the silence I'm enjoying. Then, I'll feel comfortable with a little overclock action on the CPU.

Now I need to focus my attention on my GPU so I can ensure its cool and efficient. Any ideas how to test a GPU? I'm not a big fan of Furmark since its known to fry GPUs. Maybe MSI Kombuster? Is there any way to help cool a GPU? Slot cooler or something like the Azenx Blitztorm? I'm not sure how quiet they are, but I'm curious about them.

Thanks for all the ideas / help.

Cod
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by Cod » Sat Jan 19, 2013 1:06 am

On a similar topic, what is the best fan orientation for the NH-L12? Push-pull?

efahl
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Re: Creating the Most Efficient / Quiet Air Cooling

Post by efahl » Sat Jan 19, 2013 10:42 am

Cod wrote:After doing some testing last night, it turns out using a piece of cardboard on each side of the case lowered temps by 2-degrees. Using the left side fan as an exhaust made no difference during the tests.
Not much effect, but like I said, it didn't cost much either. :)

Keep us updated on your solution.

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