In my 10/16 entry, I pointed out one way to speed up DreamWeaver MX. I have a little more detail and a couple more ideas now.
I had mentioned how you could see Edit Site, then on the "Advanced" tab, in "Local Info" turn off "Refresh Local File List Automatically". I didn't point out that the same setting exists in the "Testing Server" field there as well. These will be a big help with respect to the speed of switching in and out of DWMX. This feature is intentional as it's trying to detect if while you were out of DWMX you were perhaps creating new files (such as when folks do indeed switch out to Studio/HomeSite). But if you don't make such file additions/deletions, or if mostly you're switching out to read email, etc, then this "auto refresh" is an expensive operation. Turn it off and much slowness will go away.
Similarly, the "Remote Info" section of the Advanced tab has a checkbox "automatically upload files to server on save", again to keep your remote machine in sync. Maybe you won't really want that feature enabled (and it will certainly slow down all saves). This feature is available in all the forms of remote access (ftp, local/network, RDS, SourceSafe and WebDAV).
Some have also suggested turning off Virus checking of the DWMX "Config" directory, though I've not experience that doing much good (but I may have gained so much with these other changes that it didn't add much).
I'd welcome anyone else's thoughts. This seems an important problem for so many that it would be useful to gather some ideas.