Originally Posted by nleksan
I currently have 4x NZXT RF-FN140LB 140mm case fans (62cfm), 6x Bgears Blasters 140mm rad fans (103cfm), and 4x Koolance 120mm rad fans (107.4cfm). I will be switching the case fans to Bitfenix Spectre Pro PWM 140mm fans which push up to 122cfm with 2.8mmHg static pressure at maximum. This is in a Switch 810 case, with a 420 rad in the top (push pull) and a 240 rad in the bottom (push pull), and I am experimenting with the case fans orientation but I think I will be removing the internal HDD Cage Fan to better fit my reservoir, so good airflow (or large volume) becomes even more important.
I would suggest going with 140mm fans over 120mm if you have the option, as they simply have the ability to move more air at a lower fan speed.
A few guidelines I go by, regardless of size:
- Static Pressure is the most important factor in an intake fan that has any possible obstruction (HDD Cage, Filter, or even a mess of wires)
- Airflow Volume is the most important factor in an exhaust fan as they generally have one mostly-minimal restriction, the case's rear fan grill
- Never mount an expensive sleeve bearing fan horizontal, or any sleeve bearing fans you can't afford to replace
- Positive Pressure is generally more appropriate than negative pressure (always exceptions, not a hard rule)
- Large fans (200/230/etc) are good for keeping air moving in a case but their generally awful static pressure limits their usefulness as an intake fan where there is anything significantly obstructing airflow
- Front+Bottom Intake and Top+Rear Exhaust is NOT always the ideal configuration
- EXPERIMENT! Try out numerous configurations to see the effects on each component's temps before deciding