pwm fan

I've discovered that my motherboard has pwm fan control on the cpu fan header only. The other fan headers control them via voltage. As such my case fans have higher minimum speeds. I would like to know if there is a controller that provides true pwm control over fans or failing that the best way...

'Ey lads, in a bit of a bind. See, the 92mm fan supplied with the TX3 Evo isn't exactly...Good. I've just about reached it's actual life expectancy (bought it in early 2012), and oh god does it make a racket when my CPU is being put through it's paces. Trouble is, there aren't any decent 92mm...