HP Z420 with fanless GPU

[hstm]

Hi,

I've recently replaced the NVIDIA Quadro 2000 with a ZOTAC GTX 750 Zone with passive cooling. Since that change, the rear case fan runs at a very high speed, so that my desktop is much louder than usual.

My suspicion is that the motherboard's intelligent fan control is trying to somehow compensate the "0 rpm fan speed" reported by the GPU - which is totally ok since the GPU has passive cooling. 

This issue is reproducible. As soon as I switch back to the (fan-equipped) NVIDIA Quadro 2000, the desktop remains almost totally silent.

Is there a way to convince the motherboard to just ignore the missing fan speed of the passive cooled graphics card so that the rear fan remains silent? 

Thanks,

Helge

[BambiBoom_Z]

hstm,

It may be that BIOS has a setting that detects the presence of a GPU fan and signals the fan controller to increase RPM,  communicating through the various fan connections. If however, there is no return signal for a fan, it increases the speed of other system fans. This is guessing.

However, HP z-series are sold with fanless versions of Quadro NVS, but these are very understressed 2D-only GPU's, so it may be that with a 3D gaming  GPU, the system temperatures are rising to a level that triggers a protective mode.  Have you checked the temperatures in the z420 for CPU and GPU?  It may be that a GTX 750 under load is simply running too hot.  Looking at the HWMonitor in my local z420, the Xeon E5-1660 v2 is 45C and the Quadro K4200 is 48C.  The fans are all running at about 2200RPM- 31% of maximum.  > What do you see on your z420?

It may be easiest- and safer- to change to a GTX 750 having a fan. If, however, the 750 is running too hot and changing it is impractical, you can add a PCIe fan card set to conduct air to the chipset/ cast heatsink side if there is an open slot.

The z-series are very quiet.  We have two z420's and a z620, all with Quadros: K4200, K2200, and 4000 and these under the various desks are inaudible with any sound present of any kind  With only the air condtioning on  I can't hear these systems from 1' away.  It's never quiet enough in the  office to hear these.  It's a different story with the Dell Precisions (390, T5400, T3500, T5500) but they are not too bad either.  The T5400 is the loudest as the 32GB of DDR2 RAM runs very hot  and the system has enthusuastic memory fans. 

I think that by type, GPU fans are the quietest fans anyway- it's the CPU fan that makes more noise. A fanned version would certainly be quieter than the roaring fsystems fans.

Cheers,

BambiBoom_Z

[hstm]

BambiBoom_Z,

Thanks for the reply.

It doesn't seem to be a heat problem. HWMonitor shows almost the same CPU and GPU temperatures for both GPUs:

fanless GTX 750:

- CPU cores at about 39C

- GPU at 37C, fan 0 rpm (30%)

NVIDIA Quadro 2000:

- CPU cores at about 40C

- GPU at 39C, fan 2250 rpm (33%)

If I disable the rear fan, temperatures increase by 1-2C which shouldn't be a problem.

So this indicates that the BIOS has a problem with the missing fan signal. I didn't find a BIOS setting to change this behavior, so my next step will be to try a GTX card with a fan.  I'll update this thread with the results.

[BambiBoom_Z]

hstm,

Thank you for the update.

Just to understand the situation:

1. Is the BIOS the latest version- 3.88 ?

2. Check in BIOS and go to I thnk Advanced > Thermal and see what it says.

3. Is the driver the correct and t latest version?

4. Are you running both the Quadro 2000 and GTX 750 at the same time?

___If so, try the system with one at time, always placing it in the PCIe x16 slot closer to the top.  If the problem persists with the GTX 750 alone, then I'd recommend a replacement having a fan.

___If the problem goes away, and the system reset both cards in the system, with the Q2000 in the upper PCIe X16, go into BIOS and select the Q2000 as the primary GPU. If the fan speed is normal.

Cheers,

BambiBoom_Z

[hstm]

BambiBoom_Z,

Thanks for your reply.

1. Yes, it's 3.90 (June 2016). I've tested it with 3.88 before that, the results were the same.

2. Advanced > Thermal is set to the lowest fan setting

3. Yes. The driver's version is 368.81.
4. No. I've tested one graphics card after the other. With the Quadro installed, my Z420 remains silent (after the usual bootup fan test). With the GTX installed, the case fans of my Z420 run at a very high speed right after the bootup fan test (they don't run at maximum speed, but much faster than required).

[BambiBoom_Z]

hstm,

It's interesting.  If the CPU fan or the memory running there is a "fan not detected error message, for the system fan to be running at high speeds, it seems there must be a sensor/ fan control interlink triggering that increase in RPM.

You might go into BIOS and set the fan speed up three asterisks and see if teh behavior changes.

If the system fans are quiet, I'd say consider adding a fan card or change the GTX 750 to a fanned version.

If there is no change and the system fans are still roaring, then it's being triggered by the sensor fan interlink through BIOS - it may be panicing because it thinks there is no GPU fan- but I'm not certain how to solve that one.  Anyway,  as mentioned, these system were sold with fanless Quadro NVS..

What are the CPU tempertures running?

Cheers,

BambiBoom_Z

[hstm · Accepted solution]

BambiBoom_Z,

You're right, it's interesting.

The CPU cores have a max of 51C.

Tonite I'll get a GTX 950 with fans for testing. If it's successful, I'll just drop the fanless GTX.

Thank you for your support.

Cheers,
Helge