Here is the help topic regarding plug-ins:
Just type in APPAUTOLOAD at the command line and change the value to zero. Then close AutoCAD and restart it and the plug-ins will not load
I set mine to 0 and no plug-ins load and I think it runs a little smoother. If you want to verify that nothing is running, type APPAUTOLOADER at the command line and then hit enter for "list" and it should say that no application bundles are loaded.