Are you using Slate as material editor and the new material/map browser maybe?
Could you please test one thing (make sure Max is not running): locate the file 'SME.ini' (in you user account, path should be something like C:\Users\USER\AppData\Local\Autodesk\3dsMax\2016 - 64bit\ENU\plugcfg_ln) and change
UseOldMtlBrowser=0
to
UseOldMtlBrowser=1
Now start Max, make sure you don't open Slate and only use Classic mat-ed for this test, open a scene where you're experiencing lags. Does it still lag for you?
The new slate material browser caused all kinds of problems for me (laggy Max, material browser taking ages to open etc.) and the first thing I do with a new Max install is to make sure I'm using the old browser. Slate may run in the background to render material icons and can heavily slow down Max or even cause it to hang, like it did for me in the past.