Save your money! You only need a monster computer if you’re running it on top of an Autodesk product that requires a lot of horsepower. If you’re running Carlson on top of AutoCAD or one of their vertical applications like Civil 3d, then yes, you will want to make sure your computer is configured to meet Autodesk’s specifications.
But, Carlson’s core product and IntelliCAD can run on pretty light-duty machines.
The minimum system requirements for running Carlson with embedded AutoCAD (OEM), on top of AutoCAD and with IntelliCAD are posted here.
Updated for 2020: Carlson 2020 software will no longer run on 32 bit machines.
Note: If you are using an Nvidia video card, you will want to make sure you get the driver and updates directly from Nvidia.com and not just let Windows search for updates.
See also: Carlson KB1123: Changing graphics card settings to use your dedicated GPU on a Windows computer
See also: Carlson KB1131: NVidia video card: visual artifacts, pixelized lines, wrong text display