Howto : Emulator performance tweaks for PSP and N64 (and quality for PSX)

bilu

Nintendo 64 (Mupen64Plus-Next OpenGLES3, tested with Conker's Bad Fur Day)
From the Retroarch Quick Menu (Select-X) under Options
4:3 Resolution = 640x480 (with the parameters below, 720p and overclocking it's smooth enough for me at 2x resolution)
Bilinear filtering mode: standard
Noise emulation: false
Framebuffer emulation: true
LOD emulation: false
Color buffer to RDRAM : off
Depth buffer to RDRAM : off
Background mode: stripped
Hardware per-pixel lighting: false
Continuous textrect coords: off
Native res. 2D texrects : disabled
Less accurate blending m... : false
GPU shader depth write : true
Cache Textures : true
Max texture cache size: 8000
Texture filter: none
Texture enhancement: As Is
from "Filter background textures" until "Frame duplication": false
Framerate: fullspeed
VI refresh (overclock): 2200

For all changes done through the Retroarch menu using Select-X you need to save them using overrides:
Select-X > Overrides > Save Content Directory Overrides (or Game Overrides if specific changes to one game)

Speaking of which you can save generic options first and then change game-specific and save as game overrides, for Conker's I also use:
Overscan: enabled
Offset (Top): 8
Offset (Left): 14
Offset (Right): 10
Offset (Bottom): 12

Playstation Portable (PPSSPP)
Combined with the overclocking and 720p allows me to get average 23-26fps in the first fight scene of God of War : Chains of Olympus at 2x resolution :)
Also great at 2x resolution with Outrun 2006.

Menu > Settings (if you see the option "Create game config" it means you'll save a global configuration for all PSP games)

Under Graphics:
Backend: OpenGL (at least until Vulkan is available)
Simulate block transfer effects : on
Software rendering : off
Frame skipping: 2
Frame skipping type: Nr of frames
Auto frameskip : on
Alternative speed: unlimited
Alternative speed 2: disabled
Postprocessing shader: off
Fullscreen: on
Rendering resolution: 2x PSP
Buffer graphic commands: Up to 2
Hardware transform: on
Software skinning: on
Vertex cache: off
Lazy texture caching: on
Retain changed textures : off
Disable slower effects: on
Spline/Bezier curves quality: Low
Hardware tesselation: off
Upscale level: off
Deposterize: off
Anisotropic filtering: 16x (this improved performance too)
Texture filtering: Linear
Screen scaling filter: Linear
Lower resolution for effects: Aggressive

Under System:
Fast memory : on
I/O timing method: "fast (lag on slow storage)"
Force real clock: off
Change emulated PSP's CPU clock: auto
Rewind snapshot frequency : off
Memory Stick inserted: on

Playstation One
From the Retroarch Quick Menu (Select-X) under Options
Enhanced Resolution: on
Enhanced Resolution (speed hacking): on
Frame Duping: on

bilu

My other relevant threads
https://retropie.org.uk/forum/topic/27431/howto-major-performance-boost-on-retroarch-based-emulators
https://retropie.org.uk/forum/topic/27428/howto-change-output-resolution-to-720p-on-libretro-retroarch-emulators
https://retropie.org.uk/forum/topic/27430/howto-optimized-boot-config-txt

bilu

My PPSSPP version on the RPi4 is older than on my Batocera laptop.

There's a new option "Render duplicate frames to 60Hz" that improved smoothness significantly on my laptop, but I cannot test it on my Rpi4 at the moment.