I was hoping 'In the Hunt' would be improved, but I'm still getting only about 4 fps. What is it about that game that's so taxing?
The problem with the Irem V30/33 games is (if I understood well) how the frames are rendered, so the triple buffer can't do very much!
You're right; I don't know the details of FBA, but in general triple buffer doesn't make rendering faster.
What happens on vsynced double buffering is that when the app finishes rendering a frame, it has to wait until the next vsync before it can continue. On 60 fps there is 1000 / 60 = 17 ms per frame. If the app takes 20 ms to draw a frame, it misses the first vsync by 3 ms and will have to wait 14 ms for the next one. The end result is that it will run at half the refresh rate of the LCD, which is 30 fps for the Zero.
On triple buffering, there is an extra buffer between the app and the vsync page flipper. This means that if the app takes 20 ms to draw a frame, that frame is kept in the third buffer until vsync, but the app can continue immediately. As a result the app will never have to wait and can deliver a frame every 20 ms, leading to 1000 / 20 = 50 fps.
If an app takes 250 ms per frame however, it will run at 4 fps in either case.