The Gentle Typhoons are great fans.
I have 6 1850 rpms on 2 MCR320-QPs. I can turn 2 fans off and turn the other 4 down to around 1000RPM and my Core I5 750 peaks out around 55C under OCCT at 4.0 Ghz.
I also have a GTX295 on the same loop, but it was at idle during that test.