The noise didn’t really noticeably increase. And I just checked the values
reported by nvidia-settings. When idle, these always seem to jump in increments
of 30 RPM (usually between 1050 and 1080). With nouveau, the output value jumps
in increments of 60 RPM, so you are probably right and the difference is only
nominal.

In any case, I’m attaching the BIOS file obtained from nvagetbios -s prom. No
warnings were reported this time.