hey guys^^
i've experienced huge differnece with the psx emulator after i installed the 720p support pack, overclocked the dsp to 600MHz and locked the device at 900MHz CPU clock (installing the 720p support pack provides overclocking the dsp)
i don't know if installing the pack was the reason but here is my repot:

Castlevania: Symphony of the Night (U)
runs about 40-50 fps with soud enabled
settings:
core: pcsx-rearmed
sound enabled
threaded sound disabled
bios disabled
frameskip set to ntsc
advanced settings are all disabled
(if you disable sound you can disable the frameskip too and it will run as smoothly as on psx )

i hope this will help with speed improvements in psx emulation on n900