I’ll have to check the display mode on the tv and see if any other options exist. I did play it in Fill mode which kept the 4:3 resolution but I feel like that sorta defeats the purpose of using hdmi.
Well no? You are getting a digital signal which will be MUCH clearer than analog RCA.. Upscaling / fill mode is the Only way to make it bigger.
If your TV has a crappy upscale then you can look into external hardware, however seems odd this is making it choppy, does your TV have a low latency GAME mode?