I don’t know if there is a fix for this, but whenever I work with a ‘large’ object (generally over 40k polygons) there is lag when I shift control drag to select a bunch of verts or faces. Does anyone else have this problem? It’s not fixed with 2.5, and has been around since 2.3.1.
EDIT: did some more tests, and it’s laggy with even something as low as 15k polys. Shift selection works well, but whenever you include control into that to select verts in front and behind objects, it lags a few seconds before it performs the action.