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Mistakenly bought PWM case fans. Options?

Posted: Fri Jul 29, 2016 4:30 pm
by oneleaf
I am sure this happens a lot. Seeing my 4-pin headers on the motherboard, I bought a bunch of PWM Noctua case fans (NF-S12B redux-1200 PWM).

Then, I found they didn't spin up, and some research shows me the motherboard headers are PWM only for the CPU fan, but the others have a different pin-out and are meant to be voltage controlled.

I was wondering what people here might recommend. I am fine getting some manual fan controllers to stick in the case. I think the BIOS also has some options for manually setting a percentage on these fans, so I could do it like this as well, I think. Is there any reason to replace the fans with non-PWM ones? Or is it totally safe and reliable to manually control these?

Generally speaking, is it OK to always buy PWM fans and simply use voltage control when PWM is not available? Or is it important to get the right fan for the right job? Thanks for any advice!

Re: Mistakenly bought PWM case fans. Options?

Posted: Fri Jul 29, 2016 7:10 pm
by Fire-Flare
PWM fans won't be harmed in any way if they're run off a 3-pin header or undervolted.

I don't see why they wouldn't spin on your board, (unless the initial setting is too low?) but I suppose you could use a pointy object to extract the 4th pin and see if they'll work as 3-pin fans.

Re: Mistakenly bought PWM case fans. Options?

Posted: Fri Jul 29, 2016 8:36 pm
by quest_for_silence
oneleaf wrote:Then, I found they didn't spin up
If they didn't spin, maybe the voltage is under 6.5V: try to change the relevant header settings in the BIOS (or use a sw interface if available, like FanXpert or SpeedFan).

oneleaf wrote:Is there any reason to replace the fans with non-PWM ones? Or is it totally safe and reliable to manually control these?

Try: they could have a relatively high minimum speed for your needs, in case you might hook up them all to the CPU fan header using a PWM splitter (albeit depending of your hardware cooling needs).

oneleaf wrote:Generally speaking, is it OK to always buy PWM fans and simply use voltage control when PWM is not available? Or is it important to get the right fan for the right job?
No, it's not ok at all: your second question points to the right move.

Re: Mistakenly bought PWM case fans. Options?

Posted: Sat Jul 30, 2016 12:46 pm
by oneleaf
Thanks guys,
The Gigabyte board I have (old G33 platform) has very limited BIOS settings for fans. Any type of automatic fan speed setting risked having the fan not spin, so I would have to leave it on full blast. I do plan on getting a new motherboard (Skylake) soon, so I might get one that has PWM chassis fan headers.

Re: Mistakenly bought PWM case fans. Options?

Posted: Sat Jul 30, 2016 4:11 pm
by Fire-Flare
oneleaf wrote:Thanks guys,
The Gigabyte board I have (old G33 platform) has very limited BIOS settings for fans. Any type of automatic fan speed setting risked having the fan not spin, so I would have to leave it on full blast. I do plan on getting a new motherboard (Skylake) soon, so I might get one that has PWM chassis fan headers.
I can vouch for ASUS having excellent fan control; They've integrated custom speed ramping into the BIOS so we don't need to use SpeedFan anymore.

Re: Mistakenly bought PWM case fans. Options?

Posted: Wed Aug 03, 2016 9:37 am
by Neocray
Except FanXpert doesn't let you choose which temperature probe is used to set the fan control. That is its only flaw against an aging Speedfan.

Re: Mistakenly bought PWM case fans. Options?

Posted: Wed Aug 03, 2016 12:39 pm
by Button_Mash
Neocray wrote:Except FanXpert doesn't let you choose which temperature probe is used to set the fan control. That is its only flaw against an aging Speedfan.
I can't comment on FanXpert but the ASUS UEFI lets you specify which sensor to use for each fan. The only flaw is that there isn't really a good sensor to use for GPU temperature.

Re: Mistakenly bought PWM case fans. Options?

Posted: Wed Aug 03, 2016 1:27 pm
by Fire-Flare
Button_Mash wrote:
Neocray wrote:Except FanXpert doesn't let you choose which temperature probe is used to set the fan control. That is its only flaw against an aging Speedfan.
I can't comment on FanXpert but the ASUS UEFI lets you specify which sensor to use for each fan. The only flaw is that there isn't really a good sensor to use for GPU temperature.
My Asus Sabertooth Z97 Mark 2 board has headers for temperature probes that I connected to my GPU for custom fan ramping.

Re: Mistakenly bought PWM case fans. Options?

Posted: Thu Aug 04, 2016 4:29 am
by Neocray
Well, that is useful. Where did you get the probes ?
Button_Mash wrote:I can't comment on FanXpert but the ASUS UEFI lets you specify which sensor to use for each fan. The only flaw is that there isn't really a good sensor to use for GPU temperature.
I have an Asus UEFI, and it doesn't let me choose the sensor as well.
I have three system-wide monitoring tools: FanXpert (Asus Suite, actually), Speedfan and Corsair Link. Speedfan is not able to control half of the fan headers, FanXpert uses only the CPU temperature sensor, and Corsair Link is the only one to actually show the GPU sensors, but it offers no control over the fans...

Re: Mistakenly bought PWM case fans. Options?

Posted: Thu Aug 04, 2016 1:27 pm
by Fire-Flare
Neocray wrote:Well, that is useful. Where did you get the probes ?
FrozenCPU.com still carries them: http://www.frozencpu.com/products/10767 ... _-_25.html

Re: Mistakenly bought PWM case fans. Options?

Posted: Thu Aug 04, 2016 6:01 pm
by Abula
Fire-Flare wrote:
Neocray wrote:Well, that is useful. Where did you get the probes ?
FrozenCPU.com still carries them: http://www.frozencpu.com/products/10767 ... _-_25.html
Is frozen operating again? just wondering since it was one of my gotto places for certain things, but last i checked they had some issues. Have you bought from the recently?

Re: Mistakenly bought PWM case fans. Options?

Posted: Thu Aug 04, 2016 8:11 pm
by Fire-Flare
Abula wrote:Is frozen operating again? just wondering since it was one of my gotto places for certain things, but last i checked they had some issues. Have you bought from the recently?
I have not, though my research shows that some of the employees started their own company called ModMyMods, who carry three different lengths of probes:

https://modmymods.com/thermal/cable.html