well, I recommend u to stay w/ null2 plugin....
U have not much FMV in ff5 and null2 plugin rocks w ff5..
But, it s a known problem that 1.35 version is choppy w/ mdecs.
U can try lower version of this plugin but U won t be able to use save states correctly:
When u ll load a save state, ur sound will be inexistant or messed up...
Just switch the null2 plugin w/ the internal spu when U ll see a FMV.
It s the same problem w/ all the other ff cuz null2 plug is definitively the best spu for ff (at the moment)