4-pin CPU fan to 3-pin motherboard

[JBS]

My CPU fan has a 4-pin plug to connect to the motherboard, however the motherboard only has 3 pins. Is it possible to connect the fan to the board, and if so, what adapter would I need. Motherboard is an Epox 9U1697 socket 939 and CPU fan is a Freezer 64 Pro.

 

[Denithor]

If you look at the fan connection, I believe the back is set to fit onto the three pin plug (plastic rails match up to the plastic riser off the motherboard). Just line it up and it will work fine in 3-pin mode (fourth pin just gives motherboard the capacity to adjust fan speed based on temperature readings).