While the Nintendo 3DS isnít a powerhouse by any definition of the word, it can still output some pretty decent graphics and do some pretty impressive things especially in regards to emulation. Now, its emulation capabilities have been expanded even further thanks to the folks at libretro provided your device is a New 3DS/2DS (XL) model.
The New Nintendo 3DS didnít get many exclusive titles but the homebrew community used its improved capabilities to deliver good performance in PS1 and Commodore 64 titles (Vice3DS) Ė Image from linked blog post

According to a blog post on the libretro blog by Justin Weiss, some recent developments relating to PS1 emulation on the 3DS have pushed numerous original PlayStation games to playable territory on New 3DS/2DS consoles and these include:

  • PCSX4ALLís Unai renderer is now used in the 3DS builds of PCSX ReARMed which provides boosts of 10-20FPS over the previous P.E.Op.S. renderer that was being used
    • This change comes at the cost of some accuracy but an enjoyable game is probably better than a more accurately rendered one!

  • Support for the CHD format in the 3DS port which is a compression format best suited for disc images.
    • This format reduces the file size of games and also improves their loading times. Framerate dips during FMVs and loading zones also get reduced

Furthermore, full speed cores (dynarec-enabled ones) can be launched from the homebrew menu through Ď3dsxí files negating the need to litter your 3DS Menu with cores installed from CIA files to get the best experience.
To make use of the improvements mentioned above and play many PS1 games on your New 2/3DS console, follow this link to grab the latest Nightly builds. The next official release of RetroArch will implement the aforementioned improvements.