I frequently deal with the importation of massive surface files, which are sometimes solid bodies. I usually receive them in STEP format, but have found that SW is so slow at parsing the file that it's unworkable, and sometimes doesn't even work. So I've been opening them in NX, saving as PRT or Parasolid, and opening in SW.
The interesting thing I've noticed is that SW doesn't use anywhere near as much RAM as it could in parsing the file. I don't even think it exceeds 1GB as it imports. Are there any must-do's when importing large STEP, or really any other format, files? I've already disabled surface check and import diagnostics.