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Fractal Design R4 Cooling Advice - Page 5

post #41 of 42
Quote:
Originally Posted by andrei8703 View Post

Yes, i will surely try different setups. The side vent does not have a filter, that's why i did not put it as intake. Wouldn't it cause more harm by pulling dust into the case?
Also, that 2 way splitter from Noctua, it had one connector with 3 pins and one with 4. I thought it was broken, but after that i saw that both splitter supplied had the same layout.
Also these Noctua, according to my fan monitoring software, don't stay at the same RPM. I use Fan Expert from Asus, let's say i put 40% speed for 35 degrees. And it stays at about 645 RPM. But it varies, one second 640, the next 650, the next 645, the next 646 and so on. And everytime it changes the RPM, it makes a humming sound smile.gif, like a power fluctuation sound. This is way i say the Noctua make more noise than the Fractal R2. Even if i keep the Noctua's at 650 RPM, and i put the R2's at max(1000RPM), i still hear the Noctua's over the R2's smile.gif. Maybe it's a problem with Fan Expert, who knows. It's not about high RPM noise, it's about this humming.
Well that's about it.

Thank you all again with all your help, it's beautiful when you see people help each other with nothing to ask in return.
Wish you only the best, happy cooling smile.gif

Three pin fans, or four pin PWM fans set to a constant speed, never stay at a single, perfectly unchanging speed, like 700 RPM. There are several reasons for that.

The fan's motor, impeller, and bearings are not perfect, so there is bound to be small changes in its speed caused by one or more of them in combination. Remember that for a fan spinning at 1000 RPM, a 1% change is 10RPM. Fan speed specs commonly rate the lowest and highest speed to be +/- 10% of the given figures. For a 1000 RPM fan, that is +/- 100RPM. So a +/- 1% variation in a fans speed (10 RPM) at a constant input voltage is to be expected, and would be actually be excellent

The fans environment (temperature, resistance to the fan's air movement) is not completely static, and the voltage applied to the fan is never 100% stable and unvarying. The best PC PSU's will have voltage regulation that will change by a few tenths of a volt, and the voltage regulating circuitry for fans on a mother board is not designed to laboratory standards.

We also don't know how perfect the RPM reading is, and if the circuitry and software used to display it are also perfect, and don't influence the displayed values in any way. Measuring fractions of a volt in the speed signal that represents the difference between 900 and 1000 RPM is not simple. Given the whole system itself, such as the slip on, friction fit connections for the fans, to the software that creates a fan speed display (that only reads the fan's speed once a second at best, usually more than that), even if the fan's speed was perfect, the reading would not be perfectly correct.

Frankly, I would be shocked in anyone could tell the difference in the sound of a fan at 640 RPM and 650 RPM, or at least for a fan that is meant to be quiet. Also, the difference in SPL measured by a microphone, between 640 RPM and 650 RPM would be miniscule, and well below the ability of a human to discern it.

I've had HWiNFO running for almost two hours, and a Corsair AF140 set to maximum on my boards fan speed control, that it is monitoring shows the minimum and maximum speeds to be 1024 RPM and 1056 RPM. That is IMO excellent, given the entire speed monitoring system. That is, assuming it is correct. A Gelid 140MM fan whose speed should not have changed due to its temperature setting, has a range of 40 RPM between low and high speeds over that same time.

I doubt very highly you are hearing the difference between 640 and 650 RPM just caused by the fans. That difference of 10 RPM is inaudible IMO. There are fans that create little to no change in noise level when their speed changes by 100 RPM, or more. I imagine that others here will agree with that.

Something else is creating the noise you hear, as other have said. If a difference of 10 RPM is causing vibrations strong enough for you to hear, than either the fan is defective, or its mounting needs to be fixed.
post #42 of 42
Quote:
Originally Posted by andrei8703 View Post

Sorry to revive the thread after so long time.
I experimented a lot with fan positions.
The humming sound is 100% from the Noctua's.
Don't know how to explain this better, so here goes: Asus Fan Xpert is the software i use for the fans. Let's say i put the fans on 40% speed, that's about 650 rpm. The problem is (i think) that the fans don't actually stay at 650 rpm, they go to 644, 660, 654 etc. This is what causes the stupid humming sound(i think). Is there any way, any software i can use to set the fans at a specific speed? I tried speedfan, it doesn't work...
I have to say that this change in rpm is not because my cpu temp rises, my cpu temp stays the same, and the fan rpm changes.
Personally i dont have any issues atm with 4x Noctua NF-A14 PWM on my Define R4, 3 intake (2 front 1 bottom) 1 out. I did have a very wierd sound using them on the top of Arc Midi R2 blowing down, a growling sound that starts at 400rpm or so, and gradually gets louder as RPM increases, but this doesnt happen blowing up, so im assuming its a bearing/motor issue, but aside from that i have no complains on the noctua fans, really liking my setup a lot bieng controlled on pure bios, idling at 220rpm and limiting them to 650rpm where they are still quiet.
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CPUMotherboardGraphicsRAM
Intel Xeon E3-1230 SUPERMICRO MBD-X9SCM-F-O Matrox G200eW Kingston 4GB ECC DDR3 1333 
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GameMi
(14 items)
 
ServeMi
(15 items)
 
MiniMi
(9 items)
 
CPUMotherboardGraphicsRAM
Intel Xeon E3-1230 SUPERMICRO MBD-X9SCM-F-O Matrox G200eW Kingston 4GB ECC DDR3 1333 
Hard DriveCoolingOSPower
8x Hitachi 5K3000 2TB + 6x Samsung HD154UI 1.5TB Thermalright AXP-140 WHSv1 Antec CP-850 
CaseOther
Antec 1200 + 4x Cooler Master 4 in 3 2x Intel SASUC8I 
CPUMotherboardGraphicsRAM
Intel Core i3-2100T Intel DH61DLB3 Intel HD2000 Kingston HyperX LoVo 4GB DDR1333 
Hard DriveCoolingOSPower
Hitachi 5K500B Thermalright HR02 Windows 7 HP picoPSU 150XT 
Case
Lian Li Q08 
  hide details  
Reply
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