please can any one help me decide between these 2 Dell Precision M6800

-intel 4800MQ +8GB DDR3L RAM+ Nvidia Quadro K3100M
-intel 4700MQ + 16GB DDR3L RAM + AMD Firepro M6100

I need the device for CAD mainly SolidWorks, maybe some games, I've check the internet for a descent comaprion between the quadro K3100 and the Firepro M6100 but not so helpful I know that K3100M has more memory of 4GB but the Firepro has faster cores, RAM, and so on.