Age Old Case Front Intake Question: 2x140mm or 3x120mm?
This is a question I've seen asked a million times but I still don't feel like I've seen a great answer on the subject. For sake of discussion, let's assume the 120mm fans are Noctua NF-A12x25 fans and the 140mm fans are Noctua NF-A14. To boil down all the different arguments I've read into what I consider the consensus, it would be that 3x120mm fans offers a higher maximum potential CFM, while the 2x140mm fans offers a superior noise-to-CFM ratio.
So, if that's the consensus as it were, then 2x140mm setup would be superior in all situations, except in situations where volume is not a concern. Yet my intuition feels differently. While yes, 2x120mm fans would have spin a good deal faster to match 2x140mm, I'm not exactly sure how is it that 3x120mm wouldn't be able to match the CFM at the same or less volume. I've read a few different people trying to break it down with math, but to put it shortly, I wasn't quite sold on their math.