Both have their pros and cons; one is portable, the other is cheaper and so forth. I won’t be going through the full list of that, but as an architecture student; I found using a laptop is far more useful than a desktop. the portability; such as the need to show the drawings or models on screen during tutorials far outweighs the superior performance of a desktop. but in the end, if you have extra budget for BOTH desktop and laptop, then why not?
2. CPU Performance
In my two years experience as an architecture student, I would say that the most CPU intensive work I’ve ever done is presentation board compilation in photoshop. it takes me minutes to process a simple task such as resizing, moving objects; as the boards were to be done in huge size in terms of A1 paper rolls. Nevertheless, our usual tasks such as generating CAD views or perspective rendering require huge processing power - so expect to buy computers with core 2 duo with at least 2 ghz or more.
3. GPU capabilities
Many users thought that a dedicated graphics would only be useful for gaming, but 3d tasks from autocad, sketchup to 3ds max require a certain GPU capabilities. therefore, it does matters if you paid extra money to have that graphic card inside your PC, though you may not be the gaming type of person. on the other hand, few had asked me if there were difference between workstation or gaming graphics (nvidia quadro or geforce).
Well, I would say that they both does the same work, although workstation graphics is geared up towards stability while the other for peak performance. in either way, there’s a mobile GPU benchmark to help you out;