Linking FAN RPM to Cpu Temp

[Beggs74]

I'm thinking of building a new system next week based around an Asus P8P67 PRO using a Corsair H70 cooler with a couple of Viper fans. I've heard you can use the motherboard fan headers to make the the FAN RPM increase along with CPU temp.
Does anyone use this function and how effective is it?

 

[SupermotoMX]

plug the fan into a 4pin fan header, and enter bios and enable cool and quiet (for asus boards) or a similar name for gigabyte boards and you can set when the fans will start to ramp up to 100%

 

[Beggs74]

Anyone using ASUS Fan Expert?