Just to correct one thing: It has different fans front and back. I have no idea WHAT the difference is, but the front fan is NIDEC UltraFlo W12E12BS11B5-57 and the back one is NIDEC UltraFlo W12E12BS11B5-07. Both are rated 1.65 Amps and I see no visible difference between them. But if they took the effort to install two different fans in each unit (which means more complicated logistics), I'm sure they have a good reason for it. I can't find specs for the fans anywhere. If anyone has any info (or even a theory) about the reason for the different fans, I'm curious.

I just know that my newer S9s that came with these fans run as much as 20 (!!!) degrees C cooler than the old ones I have with the Delta fans.

My old ones with the Delta fans seem to max out at 4800RPM, I have seen the Nidec fans go up to 6000. I wonder if this is only the fans themselves, or maybe the new firmware is more aggressive in keeping the miner cool?