In the 16702A I put (3) NF-S12A PWM fans (120mm x 120mm x 25mm) plus (2) NF-A6x25 FLX fans (60mm x 60mm x 25mm).? The PWM fans aren't actually doing PWM, of course, but you can wire them for constant full speed operation too.? I imagine you can get the 3-pin FLX equivalent fans instead, but I think they're the same price.? No cooling problems at all, card cage a couple degrees cooler than with the stock fans.? Whisper quiet.
In the 16702B I did (3) NF-F12 industrial 2000rpm I67 PWM fans, plus the same (2) 60mm fans on the power supply.? I wanted a little more pressure (also has a little more CFM) in the back because I knew I'd be loading up the card cage with hot stuff.? Probably overkill.? It's a little noisier with these fans than with the NF-S12A fans in the 16702A, and will move papers around on my workbench if I set them near the vents.? ?But still a major improvement over the stock jet engines in terms of sound.
I do not know the published CFM and pressure ratings on the original fans, only the overall airflow through the vents with them installed (which the Noctua fans matched or exceeded according to my anemometer).? So please people don't jump all over me with your devilish Bernoulli equations and book values.? I'm just contributing what worked for me and has been working for some time without any problems in a fully loaded unit.? I'm sure I've offended the purists.
Scott
