Testing Fan noise level with PSU and Mobo

I just received my mobo and PSU, and I want to try several old fans I have to test their noise level. Is it ok to just connect the mobo to the PSU and one fan to the mobo? (nothing else would be connected to the mobo except psu and fan)

Why not just wire pin 14-15 (green + blackwire on 20/24pin) on the PSU and test the fans without mobo connected?

Just an idea.

//Christian