How are you transferring the files? If you're doing it through Nokia PC Suite then it will be slow because the data has to go via a very indirect route.
However, all modern Symbian phones support USB Mass Storage mode and that should give you full USB 2.0 speeds. Unless you've set a default in the options (Connections -> Data Cable -> Data Cable mode), the phone will ask you which mode you wish to use everytime you plug the data cable in. If you select "Data transfer" then the phone will show up as a regular drive under My Computer and everything should work nice and fast.
If you're already doing this then I have no idea what's wrong.
