This emulator is shockingly capable on this system. I've tried a game that, so far, doesn't seem to emulate well: Equestriad 2001.
Disable music, set frameskip to 1, synchronized rendering, hi-res downscaling.
Game plays surprisingly well to me with music disabled with this emulator on N3DS. Big problem though: controls randomly stop working with no recourse.
I lost my progress in beginner championship in Kentucky this way, which is a bummer. Saving on unlocking Lucinda Green didn't save my progress. Apparently you have to save after the presentation for it to actually save your progress, and I couldn't progress because controls stopped responding. Good thing beginner is easy.
Going to try playing around with instruction cache emulation enabled and see if that helps. I did with riskier rendering settings, but not with the sane settings I ended up using. Didn't make a difference before, but we'll see when I'm in the mood to lose progress yet again. Or maybe disable threaded rendering. Hmm...
When controls are working, it plays much better than I thought it would on N3DS.
On actual hardware, it plays really well. It only struggles a little bit with the framerate in show jumping events. Will have to see how it does beyond amateur. I made it to expert on PC, can't remember if I made it to veteran (probably not). Different from PC with lower draw distance and fps, but still totally playable. Try on actual hardware if you can, or look at gameplay footage.
And don't play Equestrian Showcase. The dairy mound at Burghley (you can reach it in amateur) is completely invisible and will fuck you over. Ask me how I know.

Equestriad 2001 on PC and PS1 don't have that problem; only the USA release on PS1 does.
Edit to add: Playing the game via Unirom forcing the game to output an NTSC signal on my NTSC-U PS1 stomps it. But IMO, game's timing is slightly off. Your horse moves just a little too fast. Not a huge deal, welcome even. I made it to amateur, but the timings for the jumps in cross country are a pain so far. I was surprised at how much I struggled. I had to press the jump button quite a bit earlier. Practice makes perfect. It'll be interesting to see how things progress.
Back under my rock I go. I do have one of those little PSone screens hooked up. Played through all the beginner championship, no problem.
Still have the screen hooked up, but felt like connecting the console to my Retrotink with SVideo cables for once. Usually I don't have energy to bother.
That is just how it is, IIRC.