Yes, this is normal and I believe it has always been that way. Your frame rate problem will be much less if you are zoomed in to a small area of the map. If your clipboard map is zoomed way out to represent the entire arena, your framerate will suffer a lot more.
I suspect that Hitech has spent a lot of his time and talent optimizing the cockpit views for high framerates, but [naturally] the clipboard is considered to be a more "static" tool and has therefore not had that kind of expensive attention. This small framerate impact is exactly what we should expect.