XPS 8950, aftermarket case fan issues

I do get the BIOS warning about the case fans, which I proceed past to boot.  I get the BIOS warning about the CPU fan as well, but with that the aftermarket CPU fan is still being modulated for load/temp while the case fans are not.

bequiet! Silent Wings 3 PWM 120mm fans claim 16.4 dBA @ 100% 1450 rpm. It doesn't get much more quiet than that. I am running some Silent Wings 3 140mm 3-pin fans @ constant 1000 rpm and 15.5 dBA. The "Gold Standard" Noctua NF-S12A PWM report 17.8 dBA @ 1200 rpm. Have you tried headphones?

I agree with you that the fans should be very quiet at that dB rating, but these are not.  I wonder if something is wrong with the PWM control signal coming from the Dell Mobo once the BIOS detects a different than expected fan RPM.  They are running full blast any time the PC is active....perhaps more 'full blast' than their design?  I'm looking into trying a hardware fan hub with its own temperature probes and customizable software fan curves.

I appreciate your insight, which makes sense.  I will either try aftermarket control suitable for this style fan or just reinstall the stock fans.  This is the first desktop I've ever bought vs. built and wasn't prepared for the nuances of minor limitations like this.  Otherwise, it's a pretty solid PC.

Nothing is wrong with the PWM signal. You are using very slow (but quiet) max speed fans in place of high speed fans and they are acting accordingly. Unfortunately, Dell PC's are very picky about the fans they work with.

"Or at least the ability to change them out without errors."

That was my big miss on assumption.  I can figure it out one way (controller) or the other (back to stock) and your comment has helped to arrive at the conclusion.

I hear ya. The fan thing is ridiculous. After spending as much as I did on the PC, I definitely would have paid a bit more to have BeQuiet or Noctua fans from the factory. Or at least the ability to change them out without errors.

I'm not sure what your component cooling solutions are at this time . . . but just a note that, at least for the XPS 8930, any 3-pin fan will work without throwing the diagnostic startup error. Of course they will not be modulated, but they are just case fans meant to provide an adequate air flow regime through the chassis.

I ran a slew of updates through Dell SupportAssist, some drivers and Intel performance manager packages were called for.  The fans now run silently.  They must have been on some erroneous overdrive signal prior.  No way they were meeting the 16dB fan spec, but after updates it went from vortex sound to silent operation.

I learned more about my fan issues over time and observation.  The combination of fans started running loudly again most of the time even after the SupportAssist updates.  I moved the case fans to a Corsair Commander iCue Pro hardware/software fan controller in order to put them on user-controllable curves appropriate for these fans.  That showed me that the actual majority of the sound was still coming from the CPU cooler fans.  It turns out they were not really being modulated by PWM on the motherboard.  They were not ramping up/down like the stock CPU cooler and were quieter than the ramped-up stock cooler so it wasn't immediately clear prior that the CPU fans were the primary cause of noise at this point.  After I figured that out, I moved the CPU fans also to the iCue fan controller.  Now, the entire system runs nearly silently and barely audible under hard load.  I understand there are some downsides to controlling the CPU fans via a 3rd party system that requires software services running, but this solution provides the result I really desire - especially with the apparent Dell motherboard limitations for controlling any non-stock fans.  Now using iCue control curves with BeQuiet fans it is normally 100% silent at low RPMs, very quiet under stress-test loads, and component temps are lower than the Dell stock air cooling mechanisms in all use cases.

Getting iCue working in the case with no USB 2.0 headers was another thing to figure out, which I found a good working solution.  I can comment further on that if it would be helpful to other users in the future.

To add internal USB access, I used this PCIe USB adapter:

https://www.amazon.com/dp/B081Y4NT25?psc=1&ref=ppx_yo2ov_dt_b_product_details

There are older Dell forum posts that this particular brand/controller does not work on the XPS, but with my more recent BIOS version (1.10.X) I had no issue.  I did have to install the drivers from the supplied CD rom and installed all drivers including USB 2.0.  iCue documentation and forums make it sound like it doesn't work with backwards compatible USB 3.0, but it did in my case.  I think having the USB 2.0 driver installed may be a key part of that.

The other key piece is that the specific USB card has 2 internal USB ports.  The iCue needs both and will not be recognized with a single USB connection.  I used this adapter cable to connect the iCue USB cable to the 2 internal USB ports on the PCIe card.

https://www.amazon.com/dp/B07Q8TC2ZM?psc=1&ref=ppx_yo2ov_dt_b_product_details

Now, I have the 2 USB headers on the iCue unit if I ever needed another.  Having added RAM, an additional NVMe HDD, CPU cooler, iCue and case fans, I think/hope I'm done inside the case for a long time.

I still get the BIOS warning of fan failures on boot.  It can be acknowledged with a click and then proceeds to boot.  I don't see a way around that, but it doesn't really bother me.  The fan control capability + temperature monitoring and customized curves for ultra quiet and cool operation are worth it IMO.

Side note:  some other/older forum posts recommend a StarTech PCIe USB 2.0 card that has the actual internal header pin connector and is true USB 2.0.  I started with that adapter, and learned that there are no compatible drivers for Windows 11 (online or with supplied CD ROM).  So that card was unsupported by the PC/OS and got returned.

Yes! I'm interested to know how you got the iCue working in the case with no USB 2.0 headers.

I just installed the Noctua NH-D12L CPU Cooler and I'm getting the typical BIOS error and the fan just seems to run at one speed. I'd love to be able to fix the issue with the iCue.