Give only one person write-access to the network tool palettes folder.
Each time someone with write-access opens and closes cad, a tool palette is updated. If autocad thinks two people made edits to the same palette, it will create duplicates, which is the main culprit for the horrible lag.
For the ONLY person with write-access, leave folder read-only unless working in file.
Autocad will create a Palettes folder and a AcTpCatalog.atc file in whatever tool palette directory you specify.
Normally the tool palette path is set to map to the default (eg. g:\cadd standards\tool palettes) - will build tool palettes based on AcTpCatalog.atc file; instead, set the tool palette path to bypass the AcTpCatalog.atc file (g:\cadd standards\tool palettes\palettes). This will severely decrease load time.