When it comes to AutoCAD, it does not take too much advantage of multi-core processors like a Dual Core or Quad Core. AutoCAD uses the power of a single core but there is a system variable called WHIPTHREAD that can be adjusted to use multi-core for specific functions. WHIPTHREAD lets AutoCAD use the other processors to improve the performance of regeneration and redraws for commands such as ZOOM.
The default value for WHIPTHREAD is 1. See image below for a description of each value.