Just got some corsair SP120 PWM fans and I cant regulate their speed from the CPU header on my EVGA z97 Stinger even in the BIOS. I can control them fine on other headers and have some scythe glidstream pwm fans that work with that same header just fine. It looks as though even though the SP120's are infact PWM They only respond to voltage control vs PWM signal. It would appear that my mobo's CPU header only supplies PWM signal and not voltage control as the other headers do. Can anyone verify the operation of the SP 120's ? Its also possible the PWM signal is broken on the mobo I suppose, is there a way to check proper functionality of a fan header with a volt meter?