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Case fans - PWM vs v NON PWM fans - Page 9

post #81 of 100
Quote:
Originally Posted by Cableaddict View Post

Quote:
Originally Posted by doyll View Post

Good info about the Aquaero and Swiftech pump compatability. thumb.gif

==============================

I respectfully disagree about PWM case fans being overkill and a waste of money. Variable voltage and PWM fans cost about the same. PWM splitter with PSU power or Swiftech 8-way PWM splitter hub is only other part needed to use CPU PWM signal to control case fans. That's cheaper than all but a real cheappy fan controller.

- Except in your scenario, all PWM devices will be running off the same SINGLE mobo signal. I don't see any point in that. If I'm going to put several PWM devices in my rig, I'd want completely independent control over each of them, including the point at which speed begins to increase. Thus, I'd need a very good controller, and the only one I know of right now is the Aquaero 6, which costs $220. - So yes, quite a waste of money if you don't get any real benefit from it.

- And there's also Lady Fitzgerald's excellent point: With just a PWM splitter / hub, you would not be able to monitor the speed of each device, which is a complete deal-breaker for me.


Look at it another way: One of the really big benefits of PWM is that your fans can run VERY slowly, without stalling. That could be important with a fast, powerful cpu / radiator fan. For instance, if I had a Noctua industrial 3,000 rpm fan installed for worst-case (100 degree F ambient, small case) situations, yet typically ran my pc's inside, and at less than 10% total cpu draw. However, I would never need nor want my CASE fans to vary that much. I will ALWAYS want them at at least 50% speed.

Thus, for that scenario, I would be just fine using non-PWM case fans, off the mobo's voltage-controll headers, and a single PWM cpu fan off the mobo's PWM header.

If I go to watercooling, then I'd need a deluxe controller, so as to control my PWM radiator fans and PWM pumps separately. - At that point, using PWM case fans would be fine since I already would have the extra PWM circuits in my controller. Except, of course, I would already own non-PWM case fans, installed while I was running an air cooler, since it is bad to run a OW fan off of voltage control.
Quote:
Originally Posted by cmpxchg8b View Post

Not sure what you mean by that. If I take a bunch of PWM fans, power them straight from PSU 12 V DC, split PWM signal from motherboard 4-pin header and feed it into all those fans, and can control fans' speed from BIOS and software, I'd say PWM control is working.

But yeah, checking with oscilloscope would be cool. I need to get one of those.
thumb.gif Running them the way you are is definitely using PWM signal to control. If you didn't have a PWM signal the fans would always run full speed on the 12v from PSU. biggrin.gif
post #82 of 100
Quote:
Originally Posted by cmpxchg8b View Post

Not sure what you mean by that. If I take a bunch of PWM fans, power them straight from PSU 12 V DC, split PWM signal from motherboard 4-pin header and feed it into all those fans, and can control fans' speed from BIOS and software, I'd say PWM control is working.

But yeah, checking with oscilloscope would be cool. I need to get one of those.

Yeah, that's one way of checking. Oscilloscope is cooler to look at though tongue.gif
post #83 of 100
Quote:
Originally Posted by Aibohphobia View Post

Quote:
Originally Posted by cmpxchg8b View Post

Not sure what you mean by that. If I take a bunch of PWM fans, power them straight from PSU 12 V DC, split PWM signal from motherboard 4-pin header and feed it into all those fans, and can control fans' speed from BIOS and software, I'd say PWM control is working.

But yeah, checking with oscilloscope would be cool. I need to get one of those.

Yeah, that's one way of checking. Oscilloscope is cooler to look at though tongue.gif

They are cool looking as well as useful. I haven't used, or even seen one, in almost fifty years, though.
     
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CPUMotherboardGraphicsRAM
i7-5930K Haswell-e Asus X99-E WS/USB 3.1 Visiontek Radeon 7870 2GB with 6 miniDisplayports G-Skill Ripjaws 64GB (8x8GB) DDR4 2133 
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Corsair AX760 Scratch built. Currently under construction at ... Logitech M525 El Cheapo Allsop hard plastic 
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post #84 of 100
I have recently built a new rig using ASUS X99-E WS USB 3.1 MB. This MB has 4 PWM case fan headers (as well as CPU and AUX CPU). I installed 6 Noctua PWM case fans and set them up using the FAN Xpert 3 software. All is fine. I assume the 'BIOS" knows they are PWM and is controlling the fans via PWM mode. My concern is that this board has a "Chassis Fan control setting jumper" which by default is set to BIOS control. The other setting fixes control to "4 Pin PWM"

My question is how do confirm that my PWM fans are being controlled by the 4th pin without opening the case and using a voltage tester on the pins?
post #85 of 100
One indirect way is to check fan curve in AI Suite - low RPM threshold is lower when PWM is used.
post #86 of 100
Quote:
Originally Posted by cmpxchg8b View Post

One indirect way is to check fan curve in AI Suite - low RPM threshold is lower when PWM is used.

I finally found the setting in BIOS: Advanced Mode>Monitor>Chassis Fans. Interestingly they were all 4 set to DCMode even though I have PWM fans and the jumper set to Auto. I have changed all 4 to PWM mode. You also have the choice of 5 component temperatures to use to control the fan speed. CPU, MB, VRM, PCH, T_Sensor. The T-Sensor is if you have plugged in your own sensor and placed it wherever! I chose MB temp as the control source. Any thoughs on this?
post #87 of 100
T-sensor should be taped to the back of the GPU. then you have finer control over which chassis fan gets kicked up depending on whether the game is CPU intensive or GPU intensive.
post #88 of 100
Quote:
Originally Posted by psyclum View Post

T-sensor should be taped to the back of the GPU. then you have finer control over which chassis fan gets kicked up depending on whether the game is CPU intensive or GPU intensive.

I bought a sensor ($5) and forgot to install it. I can't get to it now without taking out the Intel 750 Card in slot 7. I hate to play with anything when it is all working so well, superstitious!!!

mad.gif
post #89 of 100
one thing has always held true over the years in the computer business...

don't fix what aint broke smile.gif

so yah, if it's working fine. let it be smile.gif
post #90 of 100
Quote:
Originally Posted by psyclum View Post

one thing has always held true over the years in the computer business...

don't fix what aint broke smile.gif

so yah, if it's working fine. let it be smile.gif
Indeed! thumb.gif
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