this happened with the last 3 ships I tested for the SW conversion.
I use 2 mission for tests:
1- with 3 ships
2- with lots of ships (around 50, IIRC)
The models are high poly, with submodels, intersections, only lod0, no debris, only one 256x256 texture tiled over the whole model, and to test them I substitute the myrmiddon.
The models show no problems at all in game, in both missions, playing for many minutes.
It happen sometimes, not always, so far only in the mission with only 3 ships, that if I destroy a ship, in the middle of the explosion the game crash and return to windows with no error message.
I can't replicate the conditions of the crashes, I only know that it happen always in the middle of the blast.
It happened once in the mission with 50+ ships that the game freezed while a ship was exploding.
I couldn't return to windows or do anything, but the hdd was working crazily. I let the thing go on and started doing else, and after 10-15 minutes the game de-freezed and everything returned normal.
For this reason I suppose that it's a memory- issue (my system isn't exactly a NASA computer) and not a model issue: as said, I can't just replicate the crash since it doesn't happen frequently, if it was model-related I think it was going to happen always.
I wasn't using the most up to date FSO version (I updated it yesterday and still got no crashes).
The (unfourtunately) very few who tested (not deeply) them reported no crashes so far.