i opened mine up today. It is a Delta Electronics 2 wire 12v fan EFB0412HHD. The connector from the fan into the board is a 2 wire plug. im not certain if this is a standard plug.
I did sound tests and the PSU fan is far far louder than the thinner fan on the side of the case. I probably wouldnt even bother replacing the one on the side.
Now I just need to look for a replacement silent fan to match these specs. 40mmx40mmx20mm, 12V DC 0.15A.
Thank you for all your work Xqizit!
Took a look at the delta model you mentioned and found the following spec sheet:
http://www.delta-fan.com/Download/Spec/EFB0412HHD.pdf
I noticed that it has 8200 RPM and pushes 9.43 CFM while producing 34 dB-A noise!
Comparing that to what is available from Noctua, which others have claimed to use as a replacement fan in their NVRs, this seems like the best match:
NF-A4x20 FLX
It is 40mm x 40mm x 20mm 12V DC 0.05A
Unfortunately it only reaches 5000 RPM and pushes 5.53 CFM while producing 14.9 dB-A of noise
While it produces significantly less noise, I am not sure if this really is a good match as the air flow might not be sufficient. I am not sure if there are any other products which can match the specs yet reduce the noise.
Please let me know if you find anything and I will post an update if I do as well. Thanks again!