post #31 of 31
What ehume said.
The adapters are voltage reducers. With 12v in the lower fan speed from full speed to 1200 or 1600rpm depending on which one you use. If motherboard has variable voltage control, then it lowers the 12v to fan (at a variable rate) down to about 7v. So if you have a sound adapter that is already dropping the voltage from12v to 10v, the voltage after adpater is even lower .. if variable voltage header is putting out 7v, the 1600rpm adapter will lower that to about 6.3v. The 1200rpm adapter to about 4.5-5v and may not even keep fan running.