Non-buffered rendering causing black screen

[vsub_]

non-buffered rendering is a hack and is expected to have something to working correctly(including black screen on some games)

Phantasy Star Portable 2 shows black screen is non-buffered rendering is selected.
Also in non-buffered rendering,changing rendering resolution have no effect and the shaders don't work too.

And yes,some games look better in non-buffered rendering but some games just don't work with when it's selected.
Try lowering the cpu speed and see if you can get more speed and you can also try enabling the "disable slow effects" option
You can also try frame skipping with auto enabled