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post #7 of (permalink) Old 05-20-2019, 06:26 AM - Thread Starter
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So after looking again at Doyll's "Ways to Better Cooling..." thread I have come up with another question.

When doing a quick calculation to set up for optimum cooling is it better to use published CFM specs for fans, or if possible a review of some sort.

For instance, the Be Quiet Silent Wings 3 140 High Speed has a published CFM of 77.57, or ~78 CFM, but this is at 100% PWM/12V. If I extrapolate the data from Thermalbench, at say 35dB I would get a value closer to ~41.4 CFM. The BQSW3120HS done the same way provides ~19.5 CFM (vs 73.33 CFM published at 1005) at around 35 dB. The NF-A15 Cromax wasn't benched, but a similar Noctua fan provided ~40 CFM at 35dB.

If I use the method that Doyll wrote, and used published fan specs ...

I would have a component value of:

Noctua NH-U12A on CPU: 2 x BQSW120HS = ~73 CFM (fans in push/pull don't add to the CFM, correct? and use I know the NF-A12x25 are better, but they aren't black)
Thermalright TS140P on CPU: 1 x Noctua NF-A15 Cromax = ~86 CFM
Morpheus II on GPU: 2 x BQSW120HS = ~146 CFM (~73 CFM each)

73 + 146 = 219
86 + 146 = 232

219 - 232 CFM depending on which CPU cooler is used, so for further calculations I will just use the larger value of 232 CFM.

So in order to satisfy the requirements I need to provide at least 232 CFM of intake, which can be provided by:

Front Intake: 2 x BQSW140HS = ~156 CFM (~78 CFM each)
Top Intake: 1 x BQSW140HS = ~78 CFM

78 + 156 = 234 CFM

If I added a 2nd top intake fan I would push it up to ~312 CFM intake which would also meet the rule of thumb 25-50% more intake then component flow.

If I used the Thermalbench numbers I would be looking at

CPU: ~20 - 40 CFM (2 x BQSW3120HS or 1 x NF-A15 Cromax)
GPU: ~40 CFM (2 x BQSW3120HS)

Total ~60 - 80 CFM, 80 CFM used for further calculations.

Intake: ~82 CFM (2 x BQSW3140HS)

Using the benched data, I would need 1 less intake fan to satisfy the component need. I could also add an additional 1-2 intake fans for ~123 - 164 CFM (at 35dB), or further reduce the noise by running the fans slower to provide the same CFM.

I could also add 1 x BQSW3140HS fan as rear exhaust in order to help facilitate the flow of air out of the case (this should work like push/pull and not change my intake CFM values, correct?)

Is this the correct assumption based on what I read in the thread?
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