Thanks!
That's exactly what I needed your advice on. What setup would be the most quiet while still provide enough cooling for my neets?
I would say the more fans on a rad the better performance, which means you can run the fans at a lower speed.
Think of the Rad as a big heatsink and the fans as normal CPU fans. Without getting into the nitty gritty. The bigger the fan the slower it can run and push the same CFM, the more fans you run the slower each one can be and be the same CFM. So assuming so maintaining Rad size 1 fan will need to push out twice as much air per fan as a 2 fan setup to keep the CPU at a certain temp, and the same for a 2 fan compared to a 4. You loose a bit of the capacity on a push pull but the logic holds. A 2x120mm or 2x140mm rad just means a bigger Heat-sink and the ability to run 4 fans.
Also fan noise can stack so you need to keep that in mind as well. Though dependent on fan model, generally a 2 fans running 33-50% slower will make less noise than that one fan.
If you look at the performance of like an H60/70 versus an H80, the H80 wins by a mile and on some chips they don't perform much better than a cheaper HSF. So I think you need to look at 2 fans minimum. Then the question is are you willing to replace the fans that come with unit. If you are then want to get the biggest radiator in thickness or width that you feel comfortable with. The H100 is the most compatible (and comparable sub 30mm thick 2x120 rads). Then you have to decide whether you can run 2 fans on your CPU at a low enough level to keep the CPU as cool as you want. There is a lot of give and take here. All dependent on fan choice, ambient temps, CPU overclock, and what range your looking for. Heck even one 4770k and another without overclock can vary by a decent level on the same setup. 4 fans wouldn't need to ramp up as high as 2 would but their noise doesn't stack 1 for one but 4 fans at one speed are noisier than 2 fans at the same speed and you might find that 2 keeps the cpu in the range your looking for without ramping up to high.
That is why I like the H100i, it has a pretty configurable profile setup and even on its base setting have it set to low/quiet means at it's top end it will only clock up as high as i believe as high has for it's lowest settings. It's still in corsairs eyes even, its crown jewel and for techs as well. I mean it's compatible with just about everyone's enthusiast case, its technically capable, it's upgradable, and priced pretty well (got one I am installing in an ITX case on sale for $70). It's a great one size fits all clc. But you might find the Coolermaster or NXZT or even the H105/H110 to be better if your swapping out fans because of the larger radiator.
As for the fans themselves. I am not the best person to ask. I know static pressure matters most but noise levels vs. performance. I wouldn't know the first place to start. My H80 uses stock fans and my H100i will be using 4x Scythe 15mm Slip streams because I have to for my ITX.
Now if you don't want to swap out fans you need to read the reviews and see how noisy their fans got. Though keep in mind A.) most don't have any kind of fan control. B.) most of them don't have 4 pin PWM fans.