AutoCAD, like most Autodesk products have switched to Direct3D over OpenGL, so the need for a Quadro or FirePro “workstation card” has been diminished for a decade or so. People insist on the contrary because they simply haven’t looked into it.

AutoCAD, specifically for general 2D drafting has pretty primitive by today’s standards, thus most current graphic processors in laptops have built-in graphic adapters (IGP units) that surpass the raw output of low power discreet Quadro cards you would find in desktop workstations few years ago and will do fine.

Now, for the given budget of $400, it is not too easy to find a laptop that satisfies auxiliary requirements, mainly decent screen resolution.

You could still get a HP Pavilion 15.6″ and secure more than enough power:

• i3 CPU 7th gen (dual core) 2.4GHz
• 8GB RAM
• 1366 x 768 (HD touch) screen – which is the only shortfall really, I’d prefer more screen real-estate = more pixels.

Probably you would be better off spending $450 or so for something like a Dell Inspiron 15 5000 that ticks a few more marks:

• i5 CPU 6th gen (dual core) 2.3~2.8GHz
• 8GB RAM
• 15″ class screen 1920x1080p

All of this is unnecessary fable, it’s all over-kill components, to Run AutoCAD you need 2 things; Recommended Core i5 and Lots of Ram, but not that much actually; 8 Gbytes would be more than enough, in terms of GPU anything that supports DirectX 10 and above will run great,

If I were you, I would buy the laptop just for the portability; you can take your work anywhere without hassle.