There seems to be one game setting that significantly – and I mean very significantly – removes lag for me whether I am playing on my brawny desktop or my wimpy laptop.
“Turn off all combat chat feedback”.
As illustrated above (by the lovely Oriental Adventures), the setting is found on the Options menu, in the UI Settings tab, immediately below the dice color and text colors section.
When it is on, you lose the ability to view blow-by-blow details in your Combat window. You also lose some or all of your lag.
Seems like a fair trade to me.