Originally Posted by Retro Grouch

Maybe no performance difference at all, particularly if you ride mostly flat roads.

If you had difficulty climbing up some of the hills in your area with your previous crankset, you are going to have less difficulty climbing up the hills with your new one.
If you found yourself running out of gears and freewheeling on the downhills previously, you are going to run out of gears and find yourself freewheeling even sooner with your new crankset.