that rtg patch is very buggy it crash sometimes in the middle of the game
also using that patch the gamea runs out of sync
to play ab3d 2 the best choice is using winuae and the original exe ..
with a faster computer you can get about 25-30fps
ab3d 2 was a fraud like was the port of quake by clickboom
both games runs at about 10-15 fps on the fasters amigas equipped with 040/40 or the 060
10-15 fps is not playable or enjoyable