It depends on the tire. Many (most) wider tires are designed for commuter or city use, and have thicker treads and flat resistant layers, which make a tire slower. If you could find the exact same tire at 32mm that you use at 25mm then the 32mm tire will roll a bit faster. If you go from a 25mm silk casing racing tire to a 32mm Specialized Armadillo or Continental Gator Hardshell, your bike will almost definitely be noticeably slower.