Hi and welcome Steven!
Here is what you want to do: Uninstall OSX and install a really lightweight Linux or BSD distro. The slimmer, the better. Arch, Gentoo, Any BSD or I suppose Crunch Bang will do. Then, get yourself a nice, lightweight Window manager. See Unix P*rn for inspiration.
Just kidding. I know that’s not the answer for you. You probably love OSX like the rest of the world and want to keep it. The only thing I can tell you is: High end specs or not… software these days is BLOATED! I decided to ditch Creative Cloud for good because the amount of resources it consumes is UNREAL!
I don’t use Dreamweaver and never have. However… if you do, stop. Dreamweaver is a massive application that will gobble up all your resources… to write HTML and CSS. If you’re not already using a lightweight text editor… start there. I’ve been using vim lately and it’s awesome.
I hope you get more performance as I would want to die if my computer was slow and had to fight it all day.