Smart UV unwrap too big?

I want to unwrap an entire scene. What I do is combine all the meshes in the scene into one Mesh, and I smart unwrap and bake the whole scene at once. The new scene that I created will have about 800,000 - 1.2million verts, Will this crash blender when I try to smart UV unwrap it?

Quad Core AMD 3.4Ghz
4GB Ram
GTX 760 2GB Ram

Hi, it depends on the map size, geometry should not be a problem.
Save different versions of your .blend to be sure not loose your work.
4096x4096 need 4 times more memory than 2K texture map.

Cheers, mib