When you start an application, does your hard drive appear to do nothing for the first few seconds? Try rebooting without connecting to your network and see if applications load faster. If so, check your /etc/hosts file for the following line:
For example, my cable company gave me a long name like CPE00207*********. It's the string of characters in my bash prompt after my user name. (e.g. root@CPE00207...) I put that in there and now my apps aren't as slow any more.
If the line is not there, add it.