Today I opened the case of my 5208 and I found, that it's not the case-fan, that's really noisy, but the fan of the Delta-PSU.
It's a DPS-200PB-185 B with a 40x40x20mm fan, also from Delta Electronics. I can read 0.15A and I guess 12V (model of the fan is E..B0412H...D, can't read all of it...