CAD can often be very video card hungry, they make uber-powerful workstation cards for a reason. Since you didn't list a budget, I have no idea if this is feasible, but a dual Xeon rig with a Quadro 4 ...
“The reason why we bring up ZWCAD Touch is simple. We just want users to have one more efficient and easy option for their mobile CAD design experience,” said Daniel Huang, Product Manager of ZWCAD ...