Dell XPS notebook , can't decide

pls help me to decide.





new xps 15 rgb 1080p with GT 540 or xps 17 3d 1080p with GT 555



also i7 2620m or i7 2630qm or i7 2720qm



as a replacement desktop in view to playing med-res games, some multitasking and maybe video editing.





I understand the i7 2620m has a higher clock speed and actually costs more than the i7 2630qm quad core, is this going to be better for my use? or should i spend more and go for the i7 2720qm?



Is the GT 555 that much better for games (maybe i can get some high-res games usage aswell) than the GT 540?



Is the 15" RGB screen that much better than the 17" 3d improved wled?

I could still use the 15" RGB screen for 3d games if required on my 3d tv.