Synapse, the reference impl server, was always pretty slow. It got a lot faster with its Python 3 transition and there is a Go server in development that I think the core team means to focus on once 1.0 is out.
There are also native clients like Fractal and Quaternion that use GTK / Qt UIs that are just as fast as any other native app.
There are also native clients like Fractal and Quaternion that use GTK / Qt UIs that are just as fast as any other native app.