I wanted 40x28mm fan on the power supplies so I tried out the Delta FFB0412HN:
www.digikey.com
It fits perfectly with the existing screws, and at 6500 RPM it does not trigger any errors (in software or on the front panel). It moves a lot of air though, way more than needed even if you were to really load the power supply, and the noise is still a bit annoying if you're working right next to it in a quiet room. I actually wanted the 5000 RPM FFB0412MN which I think would be a much better choice but it was out of stock with a couple months lead time at Mouser.
For reference:
FFB0412HN-F00 Delta Electronics | Fans, Thermal Management | DigiKey
Order today, ships today. FFB0412HN-F00 – Fan Tubeaxial 12VDC Square - 40mm L x 40mm H Ball 10.6 CFM (0.297m³/min) 3 Wire Leads from Delta Electronics. Pricing and Availability on millions of electronic components from Digi-Key Electronics.
It fits perfectly with the existing screws, and at 6500 RPM it does not trigger any errors (in software or on the front panel). It moves a lot of air though, way more than needed even if you were to really load the power supply, and the noise is still a bit annoying if you're working right next to it in a quiet room. I actually wanted the 5000 RPM FFB0412MN which I think would be a much better choice but it was out of stock with a couple months lead time at Mouser.
For reference:
| RPM | Static Pressure (mmH20) | Airflow | |
| FFB0412HN (28mm) | 6500 | 6.30 | 10.59 |
| FFB0412MN (28mm) | 5000 | 3.76 | 8.05 |
| Noctua NF-A4x20-FLX (20mm) | 5000 | 2.26 | 5.53 |
