Define S Optimization

Enclosures and acoustic damping to help quiet them.

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Define S Optimization

Post by sexpot » Thu Dec 17, 2015 4:08 pm

Hey guys, looking for help regarding silent optimizations for my Define S.

Component list:

5820k CPU
Asus x99 Deluxe
MSI GTX 980 TwinFrozr
Samsung 950 Pro SSD
Corsair AX650 PSU
No Mechanical HDD
No Optical Drive

*cables will be well managed to restrict as lease air flow as possible, so no nonsense on the inside of the PC. It will likely be just 24 pin mobo, 8 pin cpu, and 2x 8pin VGA cables inside the case. Possibly a few fan cable extensions if needed.

My plan is to purchase additional sound deadening and laying it on the floor, top moduvent, side hdd mounting points on the case. Pretty much everywhere possible.
Suggestions on what fans to install? I'd be looking at 4x so it's somewhat colour coordinated and prefer silence. 3x front, 1x rear only.

The CPU I have the Noctua NH-D15S and 2x AF15 fans so that's covered. I'd connect all fans to the systemboard to modulate the fans depending on load. When idling, I'd like to get as quiet as possible (hopefully under 20dbs) and I don't mind slight ramp in noise when load. System will be overclocked on the CPU to 4.5GHz 1.35V.

What else would you guys suggest I can look into for silence?


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Re: Define S Optimization

Post by CA_Steve » Thu Dec 17, 2015 4:51 pm

My suggestion would be to do a stock build first with the two GP fans. See how it sounds, monitor the temps. Then, adjust from there. If you like the profile of the stock fans, and need more cooling, then buy more of those. If you don't like 'em, then replace 'em.

Don't think you need to stuff the case with additional sound deadening material...the heavy thin stuff is to reduce vibrational noise/ don't have a big source (rotating drives), and the case is sturdy, so not very susceptable to the other sources (fans). The thick foam is to reduce airborne noise...and it's generally not thick enough to matter much. Anyway, the best test is to try the build w/o extra materials first, and then see if there's a reason to add it.

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Re: Define S Optimization

Post by lodestar » Fri Dec 18, 2015 5:55 am

The best option is probably to buy 2 Noctua NF-A14 or NF-A15 fans and still use the 2 Fractal 140s that will come with the case. This is because the Asus X99 BIOS can enable this combination of fans to deployed quietly under idle and/or low system load situations. And at the same time still allow for the faster fan speeds needed to generate the greater volumes of airflow required when the overclocked CPU and the GTX 980 are under gaming load.

What I suggest you do with the case is to move the Fractal 140mm exhaust fan to the front to form a second intake. One of the Noctuas should be used in the rear exhaust position. The logical position for the other Noctua is the bottom intake position, next to the PSU, feeding air towards the graphics card. To get the lowest fan speeds, and the lowest noise levels with all of the Noctua fans you need to use the BIOS Silent Profile. This will run the fans from around 20% duty cycle while the CPU temperature is under 40C. Depending on ambient temperature, this should give fan speeds in the 300 to 400 speed range under idle conditions. With modern motherboards like the X99 these fan speeds are enough to keep both the CPU and motherboard temps at reasonable levels. When you start gaming the Silent Profile will automatically ramp up fan speeds. The way I would suggest you setup the Noctua exhaust fan is to plug it into the CPU_OPT PWM header on the board. CPU_OPT mirrors the settings of the CPU fan, it keeps the CPU and exhaust fan in sync. So you just need to set the Silent Profile for the CPU fan and it will automatically apply to the exhaust fan. The X99 Deluxe supports PWM chassis fans, and you can set the Silent Profile for the Noctua in the bottom position.

As far as the Fractal 140m fans are concerned the feature of the Asus X99 board that I suggest you use with them is a BIOS item that appears when you set a chassis fan to manual control. This item is Allow Fan Stop. How it works is that you set the minimum temperature under manual control to say 50C and then set Allow Fan Stop to Enabled. This means that the Fractal 140mm fans will not run at all under the CPU temperature reaches 50C, or whatever temperature you set. Something like 50C would only occur when gaming. So the effect is that under idle or low system stress conditions only the CPU fan and the 2 other Noctuas are running, the Fractal 140mm fans are off. There is no need for them to run and if they don't run it reduces noise levels significantly. Once the CPU hits 50C they will turn on, you will still get a degree of thermal control with them in something like a 700 to 1000 rpm range. The greater airflow from using the Noctua and Fractal Design in combination should help particularly to keep the GPU temperatures within check, and consequently keep the GPU fans and fan noise to lower levels than otherwise would be the case.

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Re: Define S Optimization

Post by sexpot » Fri Dec 18, 2015 11:46 am

Thank you Steve & lodestar for your suggestions. :)

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Re: Define S Optimization

Post by doyll » Sun Dec 20, 2015 8:25 am

I would change the front intakes to better pressure fans to overcome the grill and filter resistance without needing too much rpm. 3x front and 1x bottom intake, all speed controlled based on airflow demands of CPU and GPU coolers. Raising the case so there is 40-50mm clearance not only increases airflow to bottom intakes but also lowers noise levels. Same applies to removing bent grills . Back and bottom are easy to remove with a hand nibbler.

I would not use top vents at all. The key to good cooling is good airflow. Good airflow is not how much air fans can blow into and out of case. It is about removing the components' heated exhaust air without it contaminating and warming up the cool air supply to the components. The straighter the airflow is the better. Front intake to CPU and GPU with heated GPU exhaust kept away from GPU and CPU intake is key. A divider between front part of GPUs and GPU to CPU often helps. Removing all unused PCIe back slot covers and as much of the back of case as possilbe improves front to back airflow. Back of Define S is not as good as back of Define 5 .. Define 5 has a vent between side of case and PCIe slots, Define S does not, so where is all the GPU heated exhaust supposed to go?

Here is link to "Ways to Better Cooling". 1st post is index, click on topics of interest to see them. If you have questions, post them here and we can discuss them

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Re: Define S Optimization

Post by Cams » Mon Nov 14, 2016 2:55 pm

An interesting thread. I just built a new PC with a Fractal R5 case and ordered a Noctua NH-D15S cooler for an i7-6700K. Sounds like much can be achieved with fan placement. Thank you for the replies to this thread!

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