you know I bought 5 new 120mm 2000rpm Coolermaster fans for my Cosmos. Bloody thing was way too loud and the thing vibrated like mad. the sad thing was it dropped temps by maybe 7c. Not worth it for the noise.
I have been playing around with my Antec 300 on one of my crunching machines; most of the fans if you turn them up will actually create more heat to the cpu or will not make a difference at all.
You have to play around and find the happy medium, but for the Antec, lower speeds create the best cooling. on the cpu heatsink more is better for me though.
Even if I crank up the exhaust fans, it makes no difference. Kind of weird but the case cools really well.
I am currently doing research to see what my next case will be for another crunching machine and/or for my main system. I currently have at least 3 more cases I need to get