HP T740 fan control not working

[CIR-Engineering]

I just got a new T740 to run exclusively as an OPNsense box. I used an Intel X550-T2 because I need to connect to my modem (copper) at 5GB on one port, and then connect to my Brocade at 10GB on the other port (Copper SPF+ for now, but I'd obviously rather use fiber). I get 350 MB/S download speeds from my ISP this way.

The frustrating thing is that the NIC overheats at low load only! The CPU is so powerful that at normal internet usage speeds utilization rarely goes over a few percent so the fan slows way down because the CPU is under 50 degrees always (often 40 degrees). This eliminates airflow and then the NIC overheats and drops the connections. If I'm downloading at 300 MB/s the CPU utilization is 30-45%, the fan ramps up, the NIC stays cool, and I can download all day long.

I am on the newest BIOS for the t740 which is 1.14 and there is a setting in the BIOS to specify the minimum fan speed; Fan Idle Mode. I have seen a youtube video of it functioning on other HP systems. Mine however does not do anything no matter how I adjust it. The fan RPM readout does not change, and the fan does not get louder or quieter no matter where I set it... so frustrating. I tried backdating the BIOS, but HP won't allow it and says the BIOS is not compatible on my attempts. What is the point of having earlier BIOS releases on their site if I can't backdate them



Am I missing something? Has anyone been able to try "Fan Idle Mode" with an older BIOS and does it work? Does anyone know if there is a way to backdate the BIOS? Is there a hacked BIOS. There seems to be nothing in OPNsense of PFsense to allow setting the fan speed on this thin client (obviously no IPMI). I know if I could get the fan to stay spinning a little more all my problems would be solved, but right now I am SOL unless I want to chop up the case and rig up an external fan

Let's say I install Proxmox. Can anyone think of a way to give another OS like Ubuntu control of the fan and then run OPNsense both as VM's. I can't see how a VM could grab fan control though

I've spun the wheels for at least 30 hours on this. It should be soooo simple with the setting in the HP BIOS!

Thanks to all!

 

[CIR-Engineering]

A tiny bit more background. The same Intel X550-T2 functions in my unRAID server on an OPNsense VM and works flawlessly and never overheats. I have had the board for years and I know it's good.

I have tried using pwm to possibly set the fan speed, but I can't seem to find any devices in xxxsense that are seen by pwm.

There was something else I wanted to say but can't remember now... I'll edit when I think of it

 

[CIR-Engineering]

If anyone comes up with info on how to set the CPU fan to a minimum speed, please post it!!! I really would like a proper fix for this. However, until then...



Stopgap until hopefully HP fixes the firmware. I really didn't want to hack up the case, so I made an acrylic panel with a hole punched out for the added fan. The Acrylic cover is held on by magnets. The fan came out of a Brocade because I thought 40mm would work well. It shoots air right to the open area at the NIC heat sink and the hot SSD drive which is practically sandwiched up against said NIC heat sink.

I will take temperature readings with the fan pushing air in as it is, but I also want to try the fan pulling air out (also might need larger fan). Pulling may work better because the design is for the CPU fan to pull air through vents in the bottom up through the chassis. This fan may add to that air flow if it were pulling, but my concern is that it may also overpower the CPU fan and actually cause air to get sucked in against the flow of the CPU fan... I'll take temperature measurements both ways.

If HP would just fix the firmware this would not be needed

 

[CIR-Engineering]

HP posted a new firmware 1.15. It did not do anything to address the fan speed problem I am still having.

 

[RolloZ170]

i had similar with Lenovo tiny. BIOS FAN speed control is disabled...
because there is a Embedded Controller(EC) for FAN control and extra FW for that unit to update.

 

[CIR-Engineering]

Interesting. So the fan control may actually have its own firmware possibly even on a different chip?

 

[RolloZ170]

Interesting. So the fan control may actually have its own firmware possibly even on a different chip?

it is the case at least in the Lenovo Tiny, in other (not tiny) Models the BIOS FANs control is enabled, depends on the model.

 

[CIR-Engineering]

Rollo, with your insidght I decided not to wait potentially forever for HP to fix the BIOS fan control. They may never have even if they could, and based on your coments they might not be able to so... everything was really working just fine, but I decided I still wanted more cooling. I don't like things running hot so this is what it came to. I soldered onto the 12 volt rail for the PCIe slot and it already had a 100 uf filter cap on it which should keep fan noise from getting back to the PCIe.

It's the Noctua NF-A4x20 PWM with the noise reduction adapter in place. It moves a lot of air for a 40mm fan. I tried a Sunon fan I had here first, but it was quite loud and did not move nearly as much air as this fan even with the Noctura having the silencer on.

In this case, the fan needed to be very precisely placed to fit. Having the clear cover on had that I had already made was key to positioning the fan within the very tight tolerances in which it would manage to go. I still am glad I didn't screw up my case and got the fan in the right spot!