Faster than default Gnome-terminal, they can be installed via repository. They run under X and don’t require Gtk or Qt libraries…
1) xterm, is quite fast. I use it as a nice replacement with this shortcut:
xterm -fs 11 -fa "Courier 10 Pitch"
2) mrxvt is very fast, with nice tabs. I run it in default configuration, without antialiasing or background to keep good performance.