Z420 Fans at full speed

[dreadkopp]

Hello Community,

i run a modified HP Z420. Modified since i put a AMD RX480, a Nvidia GTX 750TI and some USB3 Cards in it. To provide sufficient cooling it uses a custom water cooling loop.

My problem:

I connected all Fan headers to PWM fans (no warnings after POST), however the whole machine is pretty noisy, no matter what settings i choose in UEFI -> Advanced -> Thermal -> idle Speed.

Is there anything to get this machine quiet again?

CPU and GPUs never exceed 45°C under full load. 

When i start the machine fasn are nice and quiet.

EDIT: i read that this might be due to the GPUs having/reporting no fan speed. Is there any workaround?

Specs:

Z420

Board: HP 1589

CPU: E5 2660

Ram: 8x8GB Samsung 1333 Mhz Reg ECC

GPU 1: AMD RX480 8GB

GPU 2: GTX 750TI

2x Inatek USB3 PCIe Card

A bunch of SSDs and HDDs 🙂

Operating System is Arch Linux.

Really hope someone got a idea.

Cheers

[MtothaJ]

---

@dreadkopp wrote:

Hello Community,

i run a modified HP Z420. Modified since i put a AMD RX480, a Nvidia GTX 750TI and some USB3 Cards in it. To provide sufficient cooling it uses a custom water cooling loop.

My problem:

I connected all Fan headers to PWM fans (no warnings after POST), however the whole machine is pretty noisy, no matter what settings i choose in UEFI -> Advanced -> Thermal -> idle Speed.

Is there anything to get this machine quiet again?

CPU and GPUs never exceed 45°C under full load. 

When i start the machine fasn are nice and quiet.

EDIT: i read that this might be due to the GPUs having/reporting no fan speed. Is there any workaround?

Specs:

Z420

Board: HP 1589

CPU: E5 2660

Ram: 8x8GB Samsung 1333 Mhz Reg ECC

GPU 1: AMD RX480 8GB

GPU 2: GTX 750TI

2x Inatek USB3 PCIe Card

A bunch of SSDs and HDDs 🙂

Operating System is Arch Linux.

Really hope someone got a idea.

Cheers

---

DO you have the ambient temperature sensor connected or funtioning correctly?

From what I recall you can view the readings in HP Performance Advisor.

[dreadkopp]

There is an ambient sensor? Must have missed that one, however there is no warnings whatsoever after post. I just installed windows to check with HP performance advisor.

Edit:

ah, found the ambient sensor on the connector for LED/PW/RST 🙂

HP Performance Advisor has no complaints and temps are fine.

https://imgur.com/a/3z6Ds

Also it seems like i misunderstand the idle fan settings. It was set to highest Value instead of lowest.

Setting it to lowest brings the fan speed down a bit but the rear fan is still annoyingly loud running @ 80-90% load (~1800rpm max)

So i guess there is still the problem with the 'fanless' GPUs. Any fix ? Just unplug the rear fan and accept the warnings every boot?

EditEdit:

I simply disconnected the Rear Fan.

Machine is relatively quiet now. However with the Post Warning there is no way to remotely restart the machine if needed. 

If anyone has any ideas please let me know. 

-> No, it is not possible to connect fans to the GPUs again since the connectors are shielded by the waterblocks 😕

[SDH]

I don't have a Z420 to get into, but here's what will work if yours is like the Z400 exhaust fan:

The Z400 it has a pretty generic single PWM rear exhaust fan but with the somewhat unique HP type of fan connector (brown plastic, 4 pin connector type).  This is not the standard white PWM plug you see wiht the three ridges (one on each side with the third offset in the middle area).  Just two outer ridges.

I have a listing of the HP fans of same size from prior projects.... and there are some that are lower wattage and run slower/quieter as a result.  These are 92 x 92 x 25 mm fans with the same type of plug end.

Post a pic of your rear exhaust fan and its connector on the motherboard, and if things look good I can get you the part number for the slower type fan.  Result:  quieter, no F1 block to reboot. 

You can watch temps with the free HWMonitor from CPUID.com to make sure you're running in a good range of temps after the mod.

Another approach:  Noctua has some nice 4-wire fan speed reducers, put in-line, and you can mod them carefully so the third inner ridge is shaved off and the adapter goes on the motherboard header then, and the original fan plug goes into the other end of the 3" long adapter.  I've done this too.  Don't get their 3-wire ones if you go this route.  If you don't get the PWM 4th wire involved the fan will go very fast at full 12VDC power.

You'd shave off the ridge that is not on the bottom edge in the picture.  You'll not have the two side edges, but this it will still work just fine and you'll know how to orient it on the motherboard header even with just one of the side ridges present.  It locks in place firmly.  Noctua makes a number of these, with different resistors, and there is the low noise adapter and an ultra low noise adapter, but you must have the 4-wire type to do this properly with the HP motherboards. 

You can look these up.... NA-RC6 has the stronger resistor, and would be the "ULNA".  You can also find that on Amazon under NA-SRC6.  The weaker resistor is the NA-RC7.  This is the "LNA".  I've used a bunch of these for fine tuning my builds.  I always use the ULNA on the little ultrafast northbridge coolers in the Z600 and if I add one over the Z400's northbridge heatsink.  The xw6600 has one of those too.  For the HP front case fans I always add I use a LNA.  I would not hesitate to add a LNA to your rear exhaust fan, and since you're using no rear fan right now maybe you'll be happy with a ULNA.  Noctua sells a set of 3 of the LNA type.  I've never seen a set of 3 for the ULNA.  Those are harder to find so I was happy to see the Amazon result via google of  "NA-SRC6".

You really should at least have the rear fan going to some degree......

[dreadkopp]

on the rear fan header there is a Bitfenix Spectre Pro 120mm connected 😉

This is a pretty modified Z420 XD

my current solution is having the pwm fans connected only via +/-/tach and the pwm line connected to a arduino which does the fancontrol.

Don't know if i stay with this solution or get real slow running nocuta redux (allready using those for the PSU).

I just hoped that it somehow was possible to control the fans from the motherboard 😕 

[SDH]

Then get a Noctua 3-wire LNA or ULNA for the 3 wires you're using and at least drop the 12VDC down to a lower level.

The HP approach to fan control is to get high quality fans that will run fast if hooked directly to 12VDC, and then brake the speed with their fine tuned PWM control system.  Personally I'd dump your big fast fan and get one of the slower HP PWM controlled fans I spoke of in the beginning of my post above.