I'm using the ASUS Maximus V Formula and a Corsair H100. I swapped the included H100 fans because I wanted fans with LED's so I have these:
Rated up to 2000 rpm and 12v. For the sake of clean wiring and the ability to monitor them in case of a failure I connected the three pin of both directly onto the motherboard; one on the CPU-OPT fan (the H100 itself is plugged into the CPU fan) and the other into a chassis fan 4 pin (CHA-FAN2, the connector is only 3 pin). The bios give me no option at all to alter the one plugged into CPU-OPT and have it running around 1800 rpm and the one plugged into CHA-FAN2 is running at only 1300 rpm. When I try to change the speed nothing happens.
Also, does anyone know why the H100 plugs into the CPU fan spot (it's powered, seemingly, by a separate molex connection) and if this controls anything? Is the pump speed static?