This is similar to the topic posted by sheraz.
I have 3-gigs of mem, running on a 2.8 GHz processor. I have also changed settings in the computer to favor performance over display. I hvae been trying to set up a project DEM through multiple terrain files.
I have an overall DEM downloaded from the web, and also have lidar data of the lower portion of the watershed (tin format). My approach is to convert the DEM to TIN and then merge the tin generated with the higher resolution tin data, then convert back to DEM. I know there can't be two DEMs associated with the same project, so I see