Originally Posted by cjc75
Not sure, never tried those UK3000rms'...
All I know is that the R4's are rated with some of the best Static Pressure, which is most important for pushing air through a radiator... quite a few have posted their Static Pressure specs earlier in this thread.
Their CFM however, is rather debatable. Cooler Master "claims" it is 90cfm, but many believe its actually maybe around 65 - 75; either way its still good CFM!
I have/have used the R4, Sythe S-Flex (1600 rpm), Apache, Antec Tri-cool and now the UK 2000. I can honestly tell you that the UK 2000 is the best for this rad. Noise is good enough that I'm keeping them over the S-Flex and I'm very picky when it comes to noise. I'd say that it's about the same as the R4 for noise. Static pressure and air flow through the rad is much better than any other of these fans period!