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The 6502 Still Rocks
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I know that most third part devices like the Aquaero allow PWM control down to very low levels ... even though the fan may have an internal bottom at say 20% or 25%.

Do all motherboards that have a PWM fan headers allow the PWM signal to be programmed to low levels or do some motherboard manufacturers limit the bottom in the BIOS because they assume fans won't run that low anyway?

I wasn't sure where to ask this but this section of OCN seemed like my best bet. I know it seems of little relevance generally but I'm building a device that is not a fan but uses the PWM Fan specification for control.
 

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It's getting better with a few of the latest gen of ASUS boards (where it should have been 5 years ago), but most manufacturers are terribly conservative with fan settings. Which is just stupid when using PWM. They should give us 0-100% range - let the devices translate. However, PWM fans and controllers are such a recent invention, have to expect the board makers will need a few decades to master such a complex technology.

/sarcasm.

I doubt Gigabyte will ever figure it out tho. They can barely control voltage control on their boards I've used.

For fine PWM control the Aquaero is still the best option. Or you can wait 20-30 years for the MB suppliers to catch up.
 

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The 6502 Still Rocks
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Discussion Starter #3
I know what you mean on Gigabyte boards. It's interns run amok in the BIOS on the fan control. I had hope for ASUS, MSI, ASRock, etc. Thanks.
 

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I've had no problems controlling PWM on my 1366 Gigabyte motherboards. Yes, they do have a base PWM %, but it is low enough that 900-2500rpm spec'ed TY-143 will idle down to 660-700rpm and TY-147A ilde at 300rpm. That is the same idle rpm I get when using Aquaero 5 LT, so I'm assuming that is as low as this bar goes.
biggrin.gif
 

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Assuming the fan is a 1:1 percent to rpm ratio, 20% PWM would be 500rpm on a 2500rpm fan. Few users need fans to idle at less than 500 rpm.
wink.gif
 

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Quote:
Originally Posted by doyll View Post

Assuming the fan is a 1:1 percent to rpm ratio, 20% PWM would be 500rpm on a 2500rpm fan. Few users need fans to idle at less than 500 rpm.
wink.gif
If you're talking about those TY-143's putting them at 20% makes them go at 600 RPM. They won't go lower on PWM.
 

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Quote:
Originally Posted by Loladinas View Post

If you're talking about those TY-143's putting them at 20% makes them go at 600 RPM. They won't go lower on PWM.
Because that is what they are setup to be at idle by Thermalright.
wink.gif
Didn't I test the new ones at about that just a few days ago? Like 570rpm on my MSI motherboarde? That is well within +/-10% margin of error they are rated at. Also we are assuming the motherboard 20% setting is actually 20% and that fan's PWM programing is 1:1 ratio.

Some fans are not 1:1, TY-147A is not, but TY-147 is.
These are the same fan, same motor, but have different curves
Their respective % : RPM graph is like this




Here is realtime run at different PWM %
 

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I tested some Noctuas down to 120 rpm or so. Tonight I tested the Tao Bao Gentle Typhoon down to zero on my Gigabyte board -- the calibrater kept going down by 10% increments. There was still a difference between 10% and zero %, but it did bottom out at 898 rpm.

I remember some older Noctua fans that would go to zero RPM as their PWM duty % approached and achieved zero.
 

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I can see reasons for using PWM fans that stop at 0% or even 10% PWM rate. Would be useful building a silent system at idle.
 

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Quote:
Originally Posted by doyll View Post

I can see reasons for using PWM fans that stop at 0% or even 10% PWM rate. Would be useful building a silent system at idle.
I agree. However, bet the vendors worry about getting flooded with panicked customers complaining their fancy fans stopped working!
tongue.gif
 

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Quote:
Originally Posted by MicroCat View Post

I agree. However, bet the vendors worry about getting flooded with panicked customers complaining their fancy fans stopped working!
tongue.gif
I would think any fan company marketing a PWM fan that stopped turning at 10-20% PWM signal would be advertising it .. meaning only an identity ten tea cat would complain / think it was defective when it did stop.
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