Review on Noctua NF-A14 iPPC-2000 PWM 4-Pin Heavy Duty Cooling Fan – Ultimate Performance at 2000 RPM (140mm, Black) by Aaron Masek

These are excellent fans without exception. I used it to replace the Noctua NF-A14 that's stuck in my Silverstone SG-13. The processor overheated a bit, and the case itself overheated because the fan just couldn't remove heat from the case. This 2000 RPM fan is louder but does a better job. Most importantly, everything inside the case stays much cooler. A 500rpm jump from 1500 to 2000 doesn't seem like much, but it's important for both airflow and noise, so keep that in mind when choosing between traditional Noctua fans and industrial fans. If you need more airflow, this is highly recommended.