Software to switch one fan off and fire up another?

[mikeymikec]

I'd like to compare one fan to another in a system I'm building, but the time taken to shut down, switch fans (even if it is a case of both of them being mounted already and disconnecting one then connecting the other), close the case etc is enough to throw off my memory if there's a subtle difference between the two.

The board has enough fan inputs to have both connected at the same time. I'm wondering if anyone knows of a bit of software that would allow me to switch one fan on and another off. Fan management is another fly in the ointment as well I suppose, I could find out what RPM the board's fan management pushes the fans at typically, then tell the software to use the same fan speeds, if possible.