I am experiencing huge disappointment with Precision R7910. The fan speed goes insane if I install other than factory supplied GPU (I installed Titan X Pascal). The workstation is nicely quiet with only onboard GPU. I would compare it to industrial vacuum cleaner with slight hints of jet engine. The same behavior was described here:

And here:
The reason behind is, as stated by Dell, to "protect" unsupported GPU with enough airflow to avoid overheating. Pretty unnecessary as all the current GPUs are able to tolerate pretty high temperatures and to throttle its clock down in case of overheating, if you ask me.. In the last discussion thread linked, there is statement from Dell representative (2nd page) where he suggests to contact Dell support for special IPMI commands to disable this behavior and revert to original cooling scheme. However, these commands are for older Precision and do not work in my case.
I contacted Dell support by phone, they just told me this is normal and read me a list of GPUs supported. We need however high performance GeForce, there is no offered. Dell can only supply FirePros (no go, we need CUDA) or Quadros (lower performance in out use case+outrageous price as a bonus).

We are building a prototype of specialized HW testbench, where there are several devices mounted in a rack (one of them should be R7910) and this rack is used in office environment by our testers. I could maybe understand this level of noise in a server computer but as we purchased WORKstation... Sorry this is unacceptable! If the issue is not resolved, this is a showstopper for us, we will look for some other rackmount PC vendor. These noise levels are not tolerable in an office.

Telephone support did not help me, this is my desperate call for help, hope that somebody competent from Dell will read it and find me a way how to make the fans with non-original GPU quiet again (using these magical IPMI commands maybe..?)