haven’t been really into PSP, but i’ve tried Dead or Alive 2 and Crazy Taxy 2 on Dreamcast, both stuggle to reach 60FPS, but i tried default speeds, 1750mhz, and even 2ghz. the bump to 1750 made a small improvement, probably because it also bumps the GPU to 600mhz.
the CPU is not maxed out, and increasing the internal resolution (to 720p) does not negatively impact the framerate. Enabling frameskip should allow a steady 30FPS, but that’s not the case either, it just halves the 40-50-ish fps i’d get without frameskip.
Which makes me doubt the original hardware was powerfull enough to run the games at full 60 fps.