<< How did you adjust the voltage?? How can you get it at 42.5c when your fan is running at 234rpm?! :Q >>
normally, fans are powered by yellow and black wires (dont use th mobo header, use a 4 pin molex). if you move to yellow/red instead of yellow/black, you'll run between the 5V and 12V rails, giving you 7V. a lot of fans dont turn at all with just 5V, but work great at 7V.
regarding low rpms: use bigger fans. I moved to 120mm fans (2 of them, on 7V) and that keeps my system totally cool and nearly silent all the time (the PSU and graphics card share a 120, the cpu gets the other)