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Nzxt whisper airflow optimization

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November 7, 2010 12:04:53 PM

So about a week ago I bought the nzxt whisper and built a great system inside it. After about a week of use i've come across the major flaw of this case. Airflow sucks!

Here's a brief review along with an explanation of the airflow flaw
http://www.guru3d.com/article/nzxt-whisper-chassis-revi...

I am thinking of reversing the two rear 80mm fans to intakes. I am also considering switching the fan on my PSU (coolermaster m1000). Anyone have any experience switching the fan direction on their psu?

As I see it this would make all fans in the lower compartment intake which would, hopefully, then direct plenty of cool air through the upper compartment. This would of course lower the potential airflow of the lower section but seeing as all the lower section has is the psu and two 3.5" HDD's I think it is more important to increase airflow in the upper section which contains the mobo, i7950, and radeon 6870.

What do you all think?

Also I have a coolermaster v6gt cpu cooler which almost perfectly aims its exhaust directly into the rear 120mm fan. There is about a 1" gap between the v6gt's exhaust fan and the cases 120mm exhaust fan. Would it be more efficent to remove the rear 120mm exhaust and have the cpu cooler do all the exhaust work?
a c 714 ) Power supply
November 7, 2010 12:35:04 PM

Pushing more air into the lower compartment does not solve the issue of getting more air in the upper compartment because of the barrier.
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November 7, 2010 1:50:39 PM

There are 3 gaps between the lower and upper section. Each is about 3x1". At present there is no intake for the upper section. The only exterior fan is the output at the rear.

As I see it the air flow for the upper section is already coming from the lower section as there are only very small gaps in the case which the negative pressure of the upper section can pull from so it must be pulling air from the lower section already. My goal is to make it easier.

I've noticed that my ambient temperature rises slowly. It seems to reach about the high 40's C with mild usage before reaching a plateau. I'm kind of curious to see what my ambient would plateau at while running prime95.
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a c 104 ) Power supply
November 7, 2010 2:24:03 PM

Send the system to me with 4x120mm fans of your choice :) 

/hacksaw at the ready
/drill loaded
/enable sound [insane cackle]
:) 
Moto
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a c 714 ) Power supply
November 7, 2010 3:28:59 PM

Take the middle hard drive holder in the middle of the barrier, cut a hole and install a 120mm fan blowing up.
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a b ) Power supply
November 8, 2010 6:19:53 AM

swapping the PSU fan as an intake will inadvertently raise the temp of the case - your going to throw heat from the PSU onto your hardware.

Quote:
Pushing more air into the lower compartment does not solve the issue of getting more air in the upper compartment because of the barrier.

Take the middle hard drive holder in the middle of the barrier, cut a hole and install a 120mm fan blowing up


Keep the PSU fan as is, After you've done what rolli59 suggested, make one (or two if you have the space) on the top of the case to act as exhaust

How about you get a SCYTHE KAMA BAY and have that as an intake for the top part of your case, drawing air through the front bezel.

Quote:
Would it be more efficent to remove the rear 120mm exhaust and have the cpu cooler do all the exhaust work?


The V6GT needs the rear exhaust fan to help get rid of the hot air out of your upper compartment. Using the V6GT as an exhaust as well as a cooler will cause some air to recirculate in your case.
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November 8, 2010 5:52:57 PM

So I got home from work and was feeling antsy so I opened up my pc. This is what I had to start with





I looked around inside and decided to move my HDD's to the smaller middle bay and remove the HDD bay at the far rear and the large one at the front. Unfortunatly the large front one will take more than a screwdriver to remove and I don't feel that energetic right now. I settled with removing the two smaller bays and moving the HDD lower in the bay. Why? I really couldn't tell you.


And thats exactly what I did.






I also shifted some of my cable work between the two sections.




This is how the air was flowing before


Aside from the noted vents in the pic there are no other places for air to except the seams which are very small. The largest I can find is the cd drive at the front which has about 0.5mm clearance. The CPU cooler is the coolermaster V6GT. It has 2 120mm fans in a push/pull configuration.

I am a very stuborn person. In spite of earlier comments I decided to try out flipping the fan on psu and the 2 rear 80mm fans. The problem I saw with the fan layout was that it was creating 2 zones of negative pressure. I didn't think that the front 120mm fan could match the airflow of the 120mm psu fan and the 2 80mm rear fans.

Here's how it looked after the flip, swap and remove mission.


And here's how I imagine the airflow will be now


The way I see it for this case to work I need the have air flowing through the sections in series. To do that I need the first section the air enters a positive airpressure followed by a negative airpressure in the second and then out the back. Ideally you would have the air exit out the psu. But thats not the way i've done it.

My goal for this case is for it to live up to it's name. In order to do that I've decided to optimize the airflow to get it as cool as possible while at the same time keeping it as quiet as possible. Later I may install fan controllers to get it even quieter but for now I just need to experiment to get the air direction perfect. So in that interest I decided to push the airflow to my cpu's limit.

The test is prime95 running the stability test on the In Place Large FFT's setting. I am also using PC Probe II to monitor my temps. I will run my cpu Idle for 5 minutes after booting up after it was off for over 12 hours. I will then run it through 8 tests in prime 95 recording the temperatures between completing each test. For both layouts it took 18 minutes to complete the 8 tests.

And the results are
-----------------------------CPU Temp (C)
-----------------------------Old------New
Idled for 5 minutes------46------38
100% Start----------------71------64
100% halfway------------73------67
100% Finish---------------74------68
Immediate Idle-----------50-------47
Idled for 5 Minutes-------47------42
-----------------------------Motherboard Temp (C)
-----------------------------Old------New
Idled for 5 minutes------47-------43
100% Start---------------44--------41
100% halfway------------43-------42
100% Finish--------------44--------43
Immediate Idle-----------45--------43
Idled for 5 Minutes-------47-------46
-----------------------------Northbridge Temp (C)
-----------------------------Old------New
Idled for 5 minutes------58--------56
100% Start----------------56-------54
100% halfway------------57--------56
100% Finish---------------58--------57
Immediate Idle-----------58---------57
Idled for 5 Minutes-------59--------61

I was very surprised by the Northbridge temps. I'm wondering if anyone has seen a rear case fan for the pcie1x that would blow air down onto the MoBo. Currently i'm about 60 minutes into mild usage and my northbridge temp is at 61C. That seems too high to me. Especially when my MoBo and CPU temps are at 47 and 42.

My next test will be to see if the airflow works better if I remove the rear 120mm fan. I think that it is just getting in the way of the awesome might of the V6GT. I also want to try making a shroud to direct the air directly out the back through the cpu cooler. What materials would you all recommend for making a temporary shroud? Is cardboard safe? If the shroud works I will see about having something permanent made up.
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a c 104 ) Power supply
November 8, 2010 6:08:53 PM

Looking a lot better in there man :) 

Cardboard would work as a shroud, all your doing is directing the airflow so materials irrelevant imo, but I'd say some thin plastic is probably your best option, easy to cut and work with, strong enough to take a few knocks
NB temps will be high, it works hard lol,
unless you go mental and put an aftermarket Hs on that too, but I wouldn't worry about it too much
I've used slotfans that blow out of the case, none that blow in though I'm afraid
and if noise is a concern, remember bigger fans move more air at slower rotations
Moto
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!