I'm having the same problem. I set the Driver Latency to 999 as suggested (though when I exit the MIDI/Audio Drivers Setup and then go back in the system resets this value to 987 every time). When I click Play on my song (all tracks are RT) I get the most gawd awful stuttering of all instruments. I then click Stop but the song keeps playing badly for a minute or two until the Stop command catches up and halts the song. I randomly selected other all-RT songs in my library and some play fine. I haven't tested them all yet.

I have a fast PC with Intel Core2Duo CPU @ 2GHz and 4Gb RAM using Windows 7. I have BIAB 2016 Build 427.