RE: m17x R4 Graphics upgrade to New Gen Graphics
Those cards are compatible with the Laptop because I've transfered across to an Nvidia GTX980m from a 7970m - but the things you need to get is the graphics card X bracket which you can buy from Ebay and thermal pads and paste, you also need to MOD the driver as well - I used this link to do it http://forum.notebookreview.com/threads/mr-foxs-geforce-345-20-desktop-driver-mod-for-alienware-and-...
This model and series of laptop wasn't created to support Nvidia but with the file MOD it works fine.
Aswell you may have to update your bios version depending on which one your on look through forums to see which one you need to get.
Obviously make sure you uninstall the HD7970m drivers first before installing the new card.