which grid? there are three of them, a small one that only renders +/- 10 'units' (some multiple of 10 meters is scaled to something appropriate for the size of the given model) around the selected item, a medium one that renders roughly within the object's bounding box, and a big one that renders out pretty far.
and keep in mind that the sig build is not an experimental BSP build, so if you used an experimental BSP build last time and this one now, it's a very different beast (don't remember which build you were using, I do recommend trying the experimental BSP though noting any significant differences in the experimental BSP thread).