I don't know if anyone else has encountered this problem, or may be able to help me determine the cause, but when I set my 6600GT (71.80 drivers, but I've tried many different ones) to 1080i, TT2 takes a very long time to open a file (VOB, ts, mpg) stored on the hard disk.
It works perfectly fine for any mode that isn't interlaced. What could my problem be?