Tipster Rory Rudden shares a Civil 3D tip that can help you reduce the strain on your workstation.
"Large drawings in AutoCAD Civil 3D can tax the resources on your PC and slow it down. One way of easing this is to use the Level of Detail command, which reduces the level of detail displayed as you zoom out (it does not affect the level of detail when plotting). The commands to turn the variable on or off are LevelOfDetail and LevelOfDetailOff. It's also available under the View tab > View panels > Level of Detail."
Notes from Cadalyst tip reviewer Brian Benton: The Level of Detail tool was first introduced in Civil 3D 2012. The farther out you zoom, the less detail you will see in your surface. This helps performance. Details you likely won’t be able to see at that distance anyway are not processed by your workstation. Why spend time and resources on rendering details you can’t see? If you are working with surfaces — especially large ones — this setting might be one for you to consider.