When I had a geared bike I found I was slower over my usual routes than I was fixed but I think this was down to me changing down all the time, I would always go be in a lower gear than I needed to be. If I kept at it I'm sure that would have changed though, when I ride with my geared friends it seems fairly even with fixed and geared being faster over certain points but at the end making it in the same time.
When I had a geared bike I found I was slower over my usual routes than I was fixed but I think this was down to me changing down all the time, I would always go be in a lower gear than I needed to be. If I kept at it I'm sure that would have changed though, when I ride with my geared friends it seems fairly even with fixed and geared being faster over certain points but at the end making it in the same time.