It was using Xaw, way back when :) But you're right: it's probably not running X apps over the network anymore. Back when the X protocol was designed, it was

It was using Xaw, way back when :) But you're right: it's probably not running X apps over the network anymore. Back when the X protocol was designed, it was still common that terminals were pretty spartan, whereas the servers they connected to were beefy machines. Nowadays, "terminals" with decent compute power are common (this has been the case for quite some time now), so it makes more sense to run the X clients locally in most cases. That being said, I for one still run X apps over the network fairly often, and would do so more often if many of the apps I used didn't suck so much over the network. For comparison, try running an xterm tunneled over ssh side-by-side with a gnome-terminal or something else GTK-based (also over an ssh tunnel). Play some emacs tetris or something in both. The difference is even larger when the clients in question make more use of various widgets, but I'm having a hard time coming up with a fair comparison (I'd suggest gvim compiled with Xaw or Motif versus gvim compiled with GTK2 or GTK3, but I gather you're an emacs user so that might be a poor exercise -- perhaps emacs's GUI has similar options?).