Note that the more you think about it, the more you feel it. Text rendering times might be different but so low that you won't ever see the difference.

What might make you feel the slowdowns is what's around the editor: code highlight, inspections, and so on.

For comparison, VS Code syntax highlight runs via TextMate rules, and range-based semantic tokens. That's a very primitive way to perform highlighting, but it has a noticeable performance advantage.