Skyrim: Will there be a difference I can see upgrading from HD 7770 to

Essentially, the graphics quality will be the same, but with faster framerates. If you are not able to turn up all the graphics settings on your 7770, then the 7970 will allow maximum graphics.

Now, if you were to upgrade to an Nvidia card, like the GTX 670, that would allow you to enable Ambient Occlusion, which will produce a difference in the graphical quality throughout. Ambient Occlusion in Skyrim is not possible on an AMD card.

http://www.geforce.com/optimize/guides/the-elder-scroll...