Almost necroposting here, but some fun facts.
Megaman Legends 2(PSX):
Runs at 60 FPS on very few menus.
Runs at 30 FPS during normal play.
Runs slightly slower sometimes for, what seems to be, dramatic effect.
Under water, it runs 20 FPS.
Megaman Legends 2(PSP):
Seems to run at 30 FPS both on land and under water.
Some fun speculation.
The PSX could probably handle 30 FPS, but the FPS was lowered for effect.
The PSP version runs at 30 FPS underwater due to complaints.
If anybody has a gameshark and would be willing to test a code on the real PSX to force 30 FPS, let me know.
PS: Thanks for the warning. I'll set my GPU plugin's manual speed to 30 FPS and manual override when I go underwater.