AutoCAD 2012 Civ3D lags, will not switch from layout to model, ultimately freezes

Hi,

Just got a brand new workstation (I'll have to come back with my specs), which should be MORE than efficient for my software...

Having trouble with approximately 1/3 of our drawings: when I am on the layout tab, and try to switch to model space, AutoCAD acts as though it's "thinking" (spinning cursor), but will not complete the switch. Occasionally if I go away for 10 mins or so, it will have switched by the time I come back, but usually, it will not. Have been trying to complete a fairly simple drawing for a deadline, SO frustrated! Can't figure out what the common characteristic is between the drawings that do this, they are all pretty similar content. One other CAD person has had this problem with some drawings, as well, different computer setup. Any ideas would be appreciated, I've tried the simple stuff: audit, change profiles back to default, etc. Thanks!!

Oh, computer specs are displayed under my user name...

In the options, try turning hardware acceleration on or off (opposite of what it is currently), restart the program and see what happens.

I can't remember if Civil 3D has it or not, although try with selection cycling turned off (button located near the osnaps button down the bottom of the screen).

Thank you! I had thought to make sure my hardware acceleration was ON, (which it was), but it wouldn't have occurred to me to try it OFF. Opened up a drawing that was giving me this problem yesterday, and it seems to be fixed... I'll follow up if I still run into it. Selection cycling was off, by the way.