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Minimum fan speeds: should I avoid 4-pin PWM splitters?

stratuh
By stratuh
in Cooling
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I have three free fan headers on my mobo and two front intake fans. I ended up using a splitter to plug both into one header for a cleaner cable management job.

 

Using fan curves, I'm trying to find the lowest fan speed one of the intake fans can go. Using Gigabyte's Smart Fan curving, I originally found them needing to go 20% at the minimum before they span up (even at 19%, I guess it's not enough power). This is around 500rpm. The other day I noticed they weren't spinning up anymore and I found the "new" minimum to be 30%, or 700rpm. Now I'm finding 25% works. It's not consistent, could the issue be that I'm using a splitter?

 

Both fans are Noctua NF-P14 Redux. I'm using a Silverstone splitter.

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You can test without the splitter, but also fans tend to get dirty and are not as well performing or slick as time goes on. How long have you had this configuration?

I WILL find your ITX build thread, and I WILL recommend the SIlverstone Sugo SG13B

 

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Draws 400 watts under max load, for reference.

 

How many watts do I need? ATX 3.0 & PCIe 5.0 spec, PSU misconceptions, protections explained, group reg is bad

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1 minute ago, fasauceome said:

You can test without the splitter, but also fans tend to get dirty and are not as well performing or slick as time goes on. How long have you had this configuration?

 

I got them BNIB maybe 5 days ago. It's for a new build so everything is new and clean.

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No, not a cause of problem. Both fans are wired in parallel so they don't slow down compared to having 1 fan per header on the board. PWM signal is just a signal, you can send the same signal to 1000 fans if you like and they will still work.

CPU: i7-2600K 4751MHz 1.44V (software) --> 1.47V at the back of the socket Motherboard: Asrock Z77 Extreme4 (BCLK: 103.3MHz) CPU Cooler: Noctua NH-D15 RAM: Adata XPG 2x8GB DDR3 (XMP: 2133MHz 10-11-11-30 CR2, custom: 2203MHz 10-11-10-26 CR1 tRFC:230 tREFI:14000) GPU: Asus GTX 1070 Dual (Super Jetstream vbios, +70(2025-2088MHz)/+400(8.8Gbps)) SSD: Samsung 840 Pro 256GB (main boot drive), Transcend SSD370 128GB PSU: Seasonic X-660 80+ Gold Case: Antec P110 Silent, 5 intakes 1 exhaust Monitor: AOC G2460PF 1080p 144Hz (150Hz max w/ DP, 121Hz max w/ HDMI) TN panel Keyboard: Logitech G610 Orion (Cherry MX Blue) with SteelSeries Apex M260 keycaps Mouse: BenQ Zowie FK1

 

Model: HP Omen 17 17-an110ca CPU: i7-8750H (0.125V core & cache, 50mV SA undervolt) GPU: GTX 1060 6GB Mobile (+80/+450, 1650MHz~1750MHz 0.78V~0.85V) RAM: 8+8GB DDR4-2400 18-17-17-39 2T Storage: HP EX920 1TB PCIe x4 M.2 SSD + Crucial MX500 1TB 2.5" SATA SSD, 128GB Toshiba PCIe x2 M.2 SSD (KBG30ZMV128G) gone cooking externally, 1TB Seagate 7200RPM 2.5" HDD (ST1000LM049-2GH172) left outside Monitor: 1080p 126Hz IPS G-sync

 

Desktop benching:

Cinebench R15 Single thread:168 Multi-thread: 833 

SuperPi (v1.5 from Techpowerup, PI value output) 16K: 0.100s 1M: 8.255s 32M: 7m 45.93s

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2 hours ago, Jurrunio said:

No, not a cause of problem. Both fans are wired in parallel so they don't slow down compared to having 1 fan per header on the board. PWM signal is just a signal, you can send the same signal to 1000 fans if you like and they will still work.

would a passive splitter VS powered splitter make a difference since there is less voltage available per fan on a passive splitter? I'm sure the MB header is not anywhere near it's max output but just thinking OP's issue might be due to the splitter causing a decrease in total voltage per fan in comparison to how much 1 fan would get by itself.

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1 hour ago, Kalm_Traveler1 said:

would a passive splitter VS powered splitter make a difference since there is less voltage available per fan on a passive splitter? I'm sure the MB header is not anywhere near it's max output but just thinking OP's issue might be due to the splitter causing a decrease in total voltage per fan in comparison to how much 1 fan would get by itself.

a few watts of extra load won't make that difference noticeable. The motherboard's fan headers and powered splitters' 12V current both come directly from the power supply.

CPU: i7-2600K 4751MHz 1.44V (software) --> 1.47V at the back of the socket Motherboard: Asrock Z77 Extreme4 (BCLK: 103.3MHz) CPU Cooler: Noctua NH-D15 RAM: Adata XPG 2x8GB DDR3 (XMP: 2133MHz 10-11-11-30 CR2, custom: 2203MHz 10-11-10-26 CR1 tRFC:230 tREFI:14000) GPU: Asus GTX 1070 Dual (Super Jetstream vbios, +70(2025-2088MHz)/+400(8.8Gbps)) SSD: Samsung 840 Pro 256GB (main boot drive), Transcend SSD370 128GB PSU: Seasonic X-660 80+ Gold Case: Antec P110 Silent, 5 intakes 1 exhaust Monitor: AOC G2460PF 1080p 144Hz (150Hz max w/ DP, 121Hz max w/ HDMI) TN panel Keyboard: Logitech G610 Orion (Cherry MX Blue) with SteelSeries Apex M260 keycaps Mouse: BenQ Zowie FK1

 

Model: HP Omen 17 17-an110ca CPU: i7-8750H (0.125V core & cache, 50mV SA undervolt) GPU: GTX 1060 6GB Mobile (+80/+450, 1650MHz~1750MHz 0.78V~0.85V) RAM: 8+8GB DDR4-2400 18-17-17-39 2T Storage: HP EX920 1TB PCIe x4 M.2 SSD + Crucial MX500 1TB 2.5" SATA SSD, 128GB Toshiba PCIe x2 M.2 SSD (KBG30ZMV128G) gone cooking externally, 1TB Seagate 7200RPM 2.5" HDD (ST1000LM049-2GH172) left outside Monitor: 1080p 126Hz IPS G-sync

 

Desktop benching:

Cinebench R15 Single thread:168 Multi-thread: 833 

SuperPi (v1.5 from Techpowerup, PI value output) 16K: 0.100s 1M: 8.255s 32M: 7m 45.93s

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Are you using Gigabyte's SIV fan software in Windows? Their motherboard fan settings can often not apply properly. 

If you ever need help with a build, read the following before posting: http://linustechtips.com/main/topic/3061-build-plan-thread-recommendations-please-read-before-posting/
Also, make sure to quote a post or tag a member when replying or else they won't get a notification that you replied to them.

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9 hours ago, WoodenMarker said:

Are you using Gigabyte's SIV fan software in Windows? Their motherboard fan settings can often not apply properly. 

I tried SIV out earlier this morning and it seemed to work, but again turning my PC on just now, fans weren't going.

 

image.png.afe46d84c604ee1ae9806f7cfa7d1ef6.png

 

SIV says the fan(s) should work as low as 10%, but it's showing 0rpm at 26% (what my fan curve sets it to). It's strange because it worked earlier all the way down to 10%, but turning off/on PC messes it up.

 

I'll give it a try with each fan in a separate header and see.

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I plugged both fans into separate headers, and the maximum speed reported by SIV is now 100rpm faster to 1300rpm. Things seem to work fine but I only ever notice issues after the PC's been off for a bit. I'm using the same fan curve so I'll see if it still works tomorrow.

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9 hours ago, WoodenMarker said:

Are you using Gigabyte's SIV fan software in Windows? Their motherboard fan settings can often not apply properly. 

I actually removed the gigabyte suit because of compatibility problems with the other programs i'm using ( iobit for instance ) and the double o.c,. stuff … setting memory speed in the bios, and the software package tells me fu, literally took me a day before i figured out the mem speeds had reset to their original value

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2 hours ago, stratuh said:

but turning off/on PC messes it up.

I've had similar issues with it and it seems to work after reinstalling the software a few times or after updating / reinstalling Windows. Their fan control is pretty buggy and one of the most annoying issues is when the header decides to use pwm instead of dc or vice-versa. That might be what's you're encountering that isn't allowing as low of a minimum rpm. 

If you ever need help with a build, read the following before posting: http://linustechtips.com/main/topic/3061-build-plan-thread-recommendations-please-read-before-posting/
Also, make sure to quote a post or tag a member when replying or else they won't get a notification that you replied to them.

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27 minutes ago, WoodenMarker said:

I've had similar issues with it and it seems to work after reinstalling the software a few times or after updating / reinstalling Windows. Their fan control is pretty buggy and one of the most annoying issues is when the header decides to use pwm instead of dc or vice-versa. That might be what's you're encountering that isn't allowing as low of a minimum rpm. 

It's something I noticed myself. I have it set to "auto" PWM or voltage. If I change to voltage, then PWM, it'll spike up to max RPM and then work fine. So far things seem to be working with using the two individual headers vs one controlling both.

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28 minutes ago, stratuh said:

It's something I noticed myself. I have it set to "auto" PWM or voltage. If I change to voltage, then PWM, it'll spike up to max RPM and then work fine. So far things seem to be working with using the two individual headers vs one controlling both.

The fan header can't do both pwm and dc at the same time. If you want to control fans with both pwm and dc, group them on separate headers. 

If you ever need help with a build, read the following before posting: http://linustechtips.com/main/topic/3061-build-plan-thread-recommendations-please-read-before-posting/
Also, make sure to quote a post or tag a member when replying or else they won't get a notification that you replied to them.

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