What do you think FPS means in the context of a terminal text editor? The linked page is pretty clear in what the author means: “Cursor movement and edits render under 10ms”. So FPS = 1 / latency. The link I gave measures latency; < 10ms is > 100 FPS.

(Though I doubt the statement re: Zee < 10ms latency in practical terms. I think only xterm and Terminal.app are consistently below that in terms of pure terminal latency)