pwm

hi. I noticed that two of my 80 mm non-pwm fans have a third solder point. Is this for the PWM input? If I solder a third wire here, then can the fan be operated like a 3-pin PWM fan?

[kitguru]World first review of the MSI R6970 Lightning Twin Frozr III (18 Phase PWM) The Review

i want to buy this fan *tiny.cc/6rxwa it requires 4 pin (PWM) Connector after searching the technical specification of my mobo(d102ggc2) i found "Rear chassis fan connector" *www.zshare.net/image/58831213a49221c3/ but this is 3 pin connector Is it ok to connect the 4pin...