Just call the imporvement "massive" and leave it at that.

Still massaging more speed out of it.

src/syncterm/CHANGES

@@ -6,7 +6,7 @@ Support Shell connections on Windows 10+
 Windows builds now include a .com (console) and a .exe (GUI) binary
 Better socket disconnect detection in SSH and telnets sessions
 Fix X11 mode scaling and fullscreen with minimal X servers
-Improve output performance up to 18 times
+Massively improve output performance
 
 Version 1.4a
 ------------