shant wrotei like yasamoka's idea better :P
as long as it can also control none pwm fans as well as pwm ones and should be able to read rpm through software
Now here's the thing...even with 4-pin PWM fans, you could control it with voltage stepping using 3 pins only...it's simpler, and achieves the same results, doesn't it? You could ramp them up with software automatically too. The only negative point about voltage stepping is fans that fail to rotate below a specified voltage (let's say 5V for Scythe fans), but you're not going to run them at <500-600 RPM, are you? (since higher than that they are still dead silent, and I mean silent with your ear close, I'm REALLY picky). Here's where PWM shines. But then you need a PWM controller, raising costs. This is why you don't see many PWM headers on motherboards. Almost all market fan controllers use voltage stepping, too.
