By the highly scientific method of "Tekken 3 is playable - although at 50fps - but actually very playable - even the sound doesnt sound that bad, with the switch (not the gl) driver" (vsync off, threaded video, switch-thread as the audio driver, frame duping on). Every PSX game is perfectly playable.
Worst case scenario - switch to the pal version of said game - which will play in in 50hz and therefore 50fps natively. Problem solved.
Tekken 3 (U) is the worst performing game I have encountered so far. So is it actually playable at 50fps?
*Looking at my ingame statistics*
Well... Yes.
(Number on the right is times played through the arcade mode with one character..
)
Most other games I've tried actually run at close enough to 60 fps that, I'd consider them very playable..