PPSSPP (android settings)

[GuilhermeGS2]

That depends on the games you play and the performance you get. The default settings are the balance between accury and performance. "Simulate block transfer effects" will fix some weird black boxes in some games, but it's heavy for the GPU, some games will not take advantage of this setting, so it'll make no difference if it's on or off. "Render duplicate framebuffer for 60Hz" is also very taxing, you might notice lower performance running some demaning games. Change the emulated CPU clock to 1000 won't make any difference for your normal performance, since the PSP's CPU by default runs at 222MHz and games aren't meant to take advantage over faster clocks, some games can take advantage of 333MHz overclock, but most will run the same as 222MHz. Use lower clocks than 222 to underclock the emulated CPU can help to improve performance on lower-end devices, but also will make the game's performance (framerate) unstable and also break some in-game features that depends on the CPU clock.