I got fatal error when set enable_opengl_fbo to no.
performance is like turtle when enable_opengl_vbo = no while the one above has to be yes. Hard to say, but feels like lag is still there.
Just one additional note.
I think AMD FirePro cards are used minimally. In PTC HW notes I found following support information related to Dell.
w7 ... AMD FirePro W8100 ... 15.201.2401 ... 09-Jan-2016
w10 ... AMD FirePro W7100 ... 16.50.2701 ... 10-Mar-2017
w7 ... AMD FirePro W9100 ... 15.201.2401 ... 23-Dec-2015
So my last suggestion is ... install older graphic card drivers.
LOOOL tbh didnt notice quite a lot change between old and new driver. Non gaming card, driver is the older the smaller the better.