fan speed plays a part but static pressure is more important high static pressure means it can push the air thru easier fan speed just means it moves more air but if it cant push it thru due to low static pressure then no matter how fast it spins it aint pushing shite. So I stand by my comment 60mm thick rad better than 40mm thick rad with the right fans.
Yes, you are right that static pressure is more important than fan speed in regards to performance in thicker and higher FPI rads. But nonetheless the fan speed has a big part also, since higher fan speed equals higher static pressure and more air throughput. Another important factor is 140mm fans have significantly lower static pressure than an equal speed and design 120mm fan. Which Is why I asked what size fan/rad was in question as well as fan RPM, both very important to pick the right rad.
The thicker rad does not always have better temps, it depends on how well the FPI and fan size/speed complement each other. eg if using a 140mm fan at medium to low RPM, and rad that is also 60mm thick, then I would highly recommend a lower FPI rad like Alphacool/Coolgate so the low static pressure 140mm fan can get enough airflow through the 60mm rad, otherwise performance will not be better than a 40mm thick rad in push pull.
If using a 120mm fan rad, then due to general higher static pressure of 120mm fans you can get away with higher FPI at the same thickness, but if you will be running at low RPM then again low FPI at 60mm is recommended, so it all depends.
Bottom-line: Fan size, Fan Static Pressure, Fan Speed, Rad thickness, Rad FPI are ALL equally important to match to get best performance, you simply can't say 60mm is better than 40mm without taking into account the other factors, you can say though that a 60mm rad does have more performance
potential than a 40mm rad (if same FPI), and IF and only if the other factors complement it.
