For those who don't know, SNES9XRX is a fork of an older version of SNES9XGX. Apparently, older versions of SNES9XGX have better framerates than the current version (4.5.7), I assume because those older versions have less features. So basically, SNES9XRX is focused more on performance than features.
I will be talking about the GameCube releases.
Based on what I've said, it seems like SNES9XRX is the winner, but when I compared Yoshi's Island's title screen between the latest versions of SNES9XRX and SNES9XGX, RX ran at ~10 FPS and GX ran at ~20 FPS. I immediately thought RX was worse upon seeing that, but then I tested Super Mario RPG: Legend of the Seven Stars and Kirby Super Star, and to my surprise considering what I saw with Yoshi's Island, those two games ran at slightly better framerates compared to GX. Battles in Super Mario RPG ran at 60 FPS and Kirby Super Star's intro ran at ~58 FPS. Movement on the overworld in Super Mario RPG still ran at a choppy 30 FPS though.
What I'm saying is, games with enhancement chips seem to vary in performance between the two emulators. RX does worse at Super FX, but it does better at SA-1. Both chips are taxing on the hardware to emulate.
So which one is better? It depends on the game you're trying to play. If you're playing a game that does not use special chips, both are fine options. If you're going to play a Super FX game, use GX. If you're playing SA-1, use RX. Remember when I said RX does worse at SFX but better at SA-1? I'm not sure if that goes for every game, so just test your games on both emulators and see which one works best for your game.
I think I rushed typing this, so I apologize if this was hard to read in any way.
SNES9XGX vs. SNES9XRX
Re: SNES9XGX vs. SNES9XRX
I think it's been 2 years since I last tried to find the best version of this emulator. If there haven't been any changes, SNES9XTX remains the best.
Re: SNES9XGX vs. SNES9XRX
It's because RX is based on Snes9x 1.52, whereas GX has moved on to the more accurate (albeit slower in some cases) Snes9x 1.62.3.
I'd use GX for most unless if I come across a slower game and then try RX personally.
I'd use GX for most unless if I come across a slower game and then try RX personally.

Re: SNES9XGX vs. SNES9XRX
A while ago I downloaded a version of SNES9XGX from 2010 in hope of some games running better. I remembered getting nesDS v2.x before playing Mother thinking it would run better on that version of the emulator (I did not test it on v1.3 beforehand). The game was so much glitchier on v2.x than v1.3, which ran the game almost perfectly with the obvious exception being the lower screen resolution. That's when I thought older versions of emulators were better in some cases, so I tried the same with SNES for the GameCube and SA-1 games ran smoother. Now I know why that is: SNES9X was focused more on speed than accuracy back in the day. I'm not saying older versions of emulators are guaranteed to run better.
SNES9XTX gave me a black screen when I booted it up.
SNES9XTX gave me a black screen when I booted it up.
