My motherboard has a connection for the pwr fan, but my PSU doesn't have a plug
mobo fan connector is for the pcu fan, not a power input. It supplies
the fan power and monitors its speed.
Is it usually OK to use that connection for a case fan instead?
yes - but then you wont have cpu fan speed monitoring, and the case
fan will change speed acording to cpu temp rather than case temp
heard "absolutes" on both sides, so am a little confused about it.
I have four case fans