That is a standard Micro-ATX (AKA uATX, mATX) motherboard. Any mATX board should be able to replace it.
I have a Sapphire R7 260X 2GB, and you can go 1Gb if you have a res less than 1080p, (like me), but I went 2GB for the futureproofing. It is a really good card for $130. EDIT: My rig is a great machine for Beam. Link is in sig.
*stabs multiple times in the chest* Getting a 2 gig card will not help futureproofing. Nothing is futreproof. A 780 Ti will be obselete in a couple years, just as say, a 590 is.
It does a bit. My hd 7770 was much too slow to run nfs:mw. I tested it with a 2gb 7790 and I could use high resolution textures. IMO, 2gb is even a little small now, but only for cards like the 780/290+. Otherwise the gpu will be too weak to use it all.
Just checked VRAM usage in BeamNG. It was around 550mb when just loaded, and after going around the map and all the stuff was being loaded it stayed at 837mb for a while, then I took this pic: That is at 1440x900 full settings.
My 19'' 1440x900 monitor died yesterday and I'll get a new 1080p in a few hours. I'll post the new vram usage to compare them. 1440x900: 837 mb 1920x1080: 934 mb