I orginally bought my old laptop for using CAD programs (4 years ago). It was completely rubbish for 3D CAD work and rendering.
It was a Dell Intel Core Duo 1.8Ghz, with 2GB Ram with Nvidia Quadro FX 2500 512MB graphics card which had options to change the ' Global Driver Settings' to a specific program, such as Maya, 3D Max, Solidworks and Microstation, but I never found this laptop to be of any use for 3D CAD programs/rendering.
The new Dell XPS i7 laptop that I'm looking to buy, comes with a quad processor, up to 16MB Ram and a choice of the following graphics cards:
1 GB GDDR5 for ATI FirePro M7820
NVIDIA GeForce GT 445M with 3GB