Make sure whichever laptop you choose, the hardware is certified to run AutoCAD.
Check the Autodesk - Certified Hardware list -
Autodesk - Certified Hardware - Find Recommended Hardware
System Requirements for AutoCAD -
AutoCAD 2013 - System Requirements - Autodesk
- For 64 bit machines, always double up the recommended RAM, it makes a big difference
I have seen high performance laptops, not able to render AutoCAD drawings because the graphics card was not recommended to run Autodesk drawings..