[Bazooka_Joe]

The loading time between each map is dependent on two things; your computer, and (If a MP game) the server's computer.

As Ydiss said, small adjustments (HD rotation speed, more RAM, etc) will always help, but core elements to faster load times are CPU power, RAM, and Video card, and your OS.

As for the server, loading a map (even though it's located on your PC, the client) still draws bandwidth from the server. Along with that, certian checks, such as making sure the maps are identical, and other aspects, are what can bog down you connecting to the server faster. These small aspects though, are exactly that; small. The main cause is a slow client PC.