Z420 Fan control solution

[giobra_86]

Hello everyone,
After lots of researching in this forum, in the "Maintenance and Service Guide" and in the Internet, I thought it was time to ask here.
Some threads treated this subject (such as https://community.spiceworks.com/topic/2087485-hp-z420-fan-control-isn-t-working?page=1 ), but I didn' t find them very helpful.

I 've got a refurbished Z420 v1 (Boot Block Date 12/28/2011) and I noticed that, stress-testing with CPU-Z, CPU fan won' t speed up until 80°C are hit, as to HWMonitor readings. This is with BIOS>Power>Thermal>Fan Idle Mode set to "0".

I read on other threads this is pretty normal and Xeons (E5-2680 in particular) can withstand easily that temperature; also my cooling system works very good as, when I stop the stress-testing, temperatures drop to 65°C within 1-2 seconds and in about 10 seconds it gets almost to 40°C.
Still, I would like to keep it under 60°C under load for reliability, since I' m going to run CFD simulations and CPU is going to be at 100% for hours.
I know I could set Fan Idle Mode to "6" (temperatures won' t go over 65°C), but this implies:
a) Noise increases dramatically;
b) I have to restart the PC before and after every simulation (which is pretty annoying);
c) All fans are sped up, while I'd just want the CPU fan to work some more.

So,
1) I thought about replacing the OEM heatsink with a liquid AIO system, possibly with PWM fan control, and I was thinking of Corsair ones (H80i, H100 GTX/v2 or H110i) which come with factory software for fan speed controlling. There could be some issues in fitting the radiator, but since I don' t care about aesthetics I 'll figure out some way.
OR
2) I thought about an external fan controller, but not much is being said on this.

Finally the real question:
Is it possible to do either one or the other solution on the stock Z420 motherboard?
What would be required by either solution 1) or 2)?

Thank you if you read this to the end.

Regards,
giobra

[SDH]

Here is the solution I developed and posted about in here (with nice pictures)... use the search box:

The ZX40 larger heatsink fits perfectly atop the ZX20 sockets.  The processors are not cross compatible but the heatsinks are.  Here is the one you want:  749554-001.  Go look on eBay.  Read my posts.  These bigger heatsinks have 4 instead of 3 heat tubes, and almost twice the fin surface area.  They fit perfectly under the memory fans shroud on the Z620 workstations if you have one of those.

The fan and the fan plug wiring for HP workstation heatsinks is key.  Just take your fan off your current HP ZX20 heatsink and switch it over to the ZX40 one noted.  They are perfect fits.....  I also have extra HP type 5-pin fan plug end blanks, and I used one of those to convert the wiring of the original 6-pin plug end on one of the ZX40 fans over to a 5-pin type.  The fans all have only 4 wires.... it is easy if you pay attention to detail and know how to release the wires (do it one at a time so you don't mess up the order).  I then gently reform the little metal tab and can reinsert.  Mouser was my source for those blanks.

Good thermal paste and technique is important..... I use Noctua, but there are even better ones, and Brian here has posted about one in particular that he uses.

Liquid cooling.... Bambi has posted on the use of liquid coolers in his workstations as has Brian.

I have yet to get into that and the double performance of the ZX40 heatsink I discovered was good enough for me right now, and quite straight forward.  By the way, if you are using Windows OS get the current HP Performance Advisor software and check that out.  We like that here....

[giobra_86]

Hello SDH, thank you for the reply.

I found your amazing solution in the "Z-workstation E5-1680 v2 Upgrades" thread; I have also read about liquid cooling by Bambi and Brian, they both have some impressive systems.

I use XTU and HP Performance Advisor with HWMonitor; since sensor figures are the same, I just quoted the ones from the latter.

However, speaking about cooling capability, the standard Z420 heatsink is just fine, as I' m not going to overclock anytime soon (the 2680 is staying for a while); I was just wondering if there is some way to control only the CPU fan speed to keep the CPU under 60°C, since at the moment I can' t.

The replacement idea with an AIO liquid system came from the fact Corsair has a software to control the fan speed, but if there is some other way to speed up the CPU fan I 'll be glad to try.
I thought also about an external fan controller, but I don' t know how to connect it and whether it' s possible to plug into the Z420 motherboard.

Regards,

giobra

[SDH]

Yep, there would be a way.  The standard HP fan speed control is via fast rated PWM fans, and then the HP motherboard applies PWM braking to the rotor to slow it down.  A reduction of that PWM braking makes the individual fan go faster.  The wire order from 1 to 5 is:   ground, +12VDC which stays constant, rotor RPM feedback to the motherboard, PWM control from MB out to the rotor, and the 5th pin is a ground jumper from 1 to 5.  For the ZX40 fan the 6th pin is ground jumper from 5 to 6.  You can guess how easy it is to swap out a fan plug end to convert from the ZX40 wiring back to the ZX20 wiring.

There are PWM based fan controllers, so you could pass through pin 1, 2, 3, and pass over pin 1 to 5 so you have the necessary ground jumper there.  You'd exclude the pin 4 from the motherboard but provide it from the PWM fan speed controller.  You don't want to dink with the 12VDC... but I have done that to slow down fans and still keep PWM control on the HP workstations.

The idea here is that if there is zero PWM braking (wire 4 disconnected) the fan will run at full speed being hooked up only to pins 1,2,3, and the 1-5 jumper.  If you take over the PWM wire control from the motherboard for just that one fan then you can dial up or down the PWM braking.  Believe me.... these fans can go very fast if you drop the amount of braking, and you'll be doing that for only the CPU fan.   Here is the best:

https://noctua.at/en/na-fc1

A few other things.... you can keep the case cooler by not using more memory than you really need.  Do you have a front PCIe case fan?  There is a standard one but not all came with it.  Get one if you don't.  There also is a front airflow guide that is different from the one HP made for the Z400.  It uses the power supply fan's suction to guide cooling air across the front memory bank and up and out the case via the power supply path.

[giobra_86]

Thank you for the reply, SDH.

I 'm not too familiar with electronics, so I 'll try to keep up: if I were to install a PWM 4-pin fan, pins 1, 2, 3 on motherboard should be connected to pins 1, 2, 3 on fan in the right order, pin 4 on motherboard disconnected and wire 4 on fan side connected to pin 5 on the motherboard? Basically I'd have to swap the 4 pin connector on the fan with a 5 pin one in which pin 4 isn' t wired, right?

This way, though, fan would be at full speed all the time. I hoped for something adjustable without changing motherboard, but if there isn't such a way I 'll go for the way you suggested.

Unfortunately I need that much RAM for CFD, but I thought about getting a front case fan and the inlet guide for the front side RAM slots.

Thank you very much for your help!

Regards,

giobra

[SDH]

Nope.

I'd make an adapter.that would plug in to the 5 pin motherboard header, and somehow the Noctua PWM controller would be in line for pins 1-3.  It would include a jumper from pin 1 to 5 so pin 5 sees ground at all times.  Pin 4 from the motherboard would not pass through.... it would dead end.  The equivalent of pin 4 would pass through from the adapter/Noctua device on to the fan.  You would dial up or down the CPU fan speed via the little knob on the Noctua device.

Personally I would not do this project because I'm happy with what HP has designed.  This likely is a job for a talented computer shop if you wish to proceed.  It would be a lot easier to do my first answer..... ZX40 large heatsink using your current ZX20 fan.  You have no idea yet how much better cooling performance that woudl result in..... 33% more heat tubes and allmost 100% more cooling fin surface area. 

Good luck on your project!

[giobra_86]

Thank you for the reply.

Maybe I understood your idea; I 'll get a Noctua fan controller and try to fit it in. Also I 'm probably switching to an AIO liquid cooling with 4 pin to simplify the system (just one 4-5 pin adapter instead of two) and minimize mistakes.

I 'll take some time to figure it out properly and wait for parts to arrive and then I 'm going to update the thread.

Again, thank you for your time and your patience.

Regards,

giobra

[ShadowX360]

Just wanted to say I actually did the wiring work to run an Arctic Freezer 33 CO on an HP Z420 a while back. I agree with everything you said, if I were to do this again, I would highly consider the HP part. I am actually  using that Noctua PWM control though, surprised how we independently came to the same conclusions. I had other considerations as I couldn't use the guide for the power supply. Of note, the guide is not for cooling the RAM but for guiding the hot air from the RAM away from the CPU cooler. I am using the 5.25" slots for my hard drives and I had to add in a few more fans in the front for cooling the drives so the guide was actually pushing air the other way.

[rtibby]

I've tried a Air only cooling solution to avoid the HP Liquid cooler (not easy to find a really used efficient one.. , plus liquid hazard, etc).

So I replaced the stock CPU cooler with the best Noctua Air cooler for LGA2011. 

I've kept all original fans (two reasons - I do avoid HP bios errors and I use original fans for a better cooling): rear , front , memory fan is now VRM cooler  , CPU cooler is now an additional front Fan.

Also , knowing the fact that temperature/RPM curve for Z420 is too flat ; I mean RPM for Z420 fans are speeding up only for CPU load 100% and CPU temperature hitting somewhere around 85deg - which is concerning for overclockers... , I added a external Fan speed controller : I do controle separately the 2 added Noctua Fans: the CPU one and the small rear one. 

These 2 fan speed response is a preselected curve according to a temperature sensor mounted on the CPU Noctua cooler (part of the external speed controller).

This way HP fan control is in charge for rear fan , front fan , and additional front fan (ex CPU 5 pin fan) , and the external controller is in charge for the CPU Fan and Small Noctua rear Fan.

RESULTS:

- 4.5 Ghz CPU speed (45 multiplier) can be set with XTU on all cores. It stays on 4.5Ghz on all cores if overall load of CPU is less than 100% and active or active cores is less than 6. (see photos)

- with Prime95 CPU stress blend on all cores, temperature on CPU cores is 55-60deg

- idle CPU temperature is 27-29degAll fansFan speed controllerRear Noctua 40x20 Fan4.5 Ghz overclockCPU scoreCPU stress test Prime95Core temperatures Idle 

Z420 , e5-1650v2 @ 4.5Ghz all cores , Air CPU Cooler, 32Gb RAM HP 1xR8 4x8Gb , GTX 1070 , 1Tb SSD Samsung Evo 860, 1.5Tb HDD