2011 VERY slow lisp performance!

[Serhan_BAKIR]

Hi there,
few days ago we have switched from 2008 to 2011 version of autocad. Now we are experiencing very slow performances on our automated drafting programs. such as one of our program which has been usually finishing in 10 seconds (reading data from file, calculating and drawing polylines text and hatch objects) now takes over 4 minutes to complete!!

program is compiled to vlx and contains routines with basic coding including "command" "entmake" and numerous vl* functions aswell. I have switched off every helper like osnap, polar, grid, viewcube, ribbon etc..

it seems that something has changed fundementally but what is it? please help I'm really disapointed begining day one with 2011. thanks in advance.

edit: if the lisp drawing operation is visible on the screen it is slow. If drawing takes place out of the visible area (such as zooming in too much or panning the screen out of visible area) lisp operates faster.
I hope someone out there point out a system variable to fix this behaviour