I don't know, I've found I can carry on flying a spaceship around with no issues at all on a ten year old computer.If they ultimately merge Horizons into Odyssey then I believe they will lose a lot of players.
From what I have read and experienced myself there seems to be a 50%+ drop in frames between the two versions.
After the many months and 8 patches, Odyssey basically sucks and will never port over to our console Commanders.
It's only when you get out of the ship at a settlement in my experience and then only certain ones. If you stick to doing horizons stuff it's pretty much like horizons.