I don't really have any experience with X. It appears from what I read that X has always been built from the ground up to allow windows in the WM to be transmitting over the internet, without trasmitting a bitmap (or compressed bitmap) of the entire screen (which would require at least as much bandwidth as a youtube video).

  1. Can any Linux app's GUI (whether it uses GTK or whatever) be run seamlessly over a remote connection?
  2. Is the "lag" in using the GUI remotely significantly better than a VNC?
  • If you run X (without additions like nomachine) over a WAN connection or the internet, the performance is very, very, very slow. I'd go so far to say that X over a regular internet connection is unusable.
    – Marco
    Commented Sep 26, 2013 at 19:24

3 Answers 3


X works fine locally, over a LAN, and over a WAN.

But it does use the network, and X, like all GUI-over-network protocols, is pretty intolerant of high latency.

Some applications are less high-latency friendly than others. Firefox is probably one of the worst offenders, both in terms of how much it is doing AND in terms of how little effort the programmers put into over-the-network (or indeed CPU) performance. Compare it to an xterm, which is pretty close to the other end of the scale for network-friendliness.

That said, I regularly use Firefox over a 54Mbps WiFi connection to a 100Mbps LAN, and there is barely any difference between that and a local Firefox. Clearly @Marco has other network issues going on if Firefox is taking 2 minutes to start on their 1000Mbps link.

  1. Yes. At least for the most part - I haven't had any problems with GTK or Qt applications.

  2. No. I wouldn't say it's unusably slow (if you have quite a fast connection - say 10+ Mbps - there's hardly any delay), but you're still better off using NX or even RDP.

  • “there's hardly any delay” seriously? Did you ever try to use firefox using X forwarding? The delay is dozens of seconds. Even with 1000Mbps it's unusable, since the network delay is too high and X is just too verbose and sends way to many messages. The bandwidth doens't matter at all.
    – Marco
    Commented Sep 26, 2013 at 20:09
  • Well, I'm trying it right now - 30/10 Mbps connection on the remote machine and 30/5 here, there is a noticeable delay, but it's quite usable, far from dozens of seconds. Do you have latency issues?
    – user6294
    Commented Sep 26, 2013 at 20:30
  • Apparently I do, yes. Starting firefox takes 1:37 minutes here. 100 Mbps my host, 1000 Mbps remote host. Clicking the “File” menu takes 52 seconds until it appears.
    – Marco
    Commented Sep 26, 2013 at 20:38
  • 1
    Interesting. It takes 11 seconds to start for me, and the delay is between about 0.5 and 2 seconds for menus (and scrolling web pages is, unexpectedly, quite smooth). If it matters, the remote side is Ubuntu, and the local side (I'm at work) is Windows, with putty and Xming for the X server. I would be surprised if that made such a big difference, though.
    – user6294
    Commented Sep 26, 2013 at 20:44

X11 over ssh is going to be slow. This increases greatly for something like firefox. An easy boost is to enable compression "-C". Beyond that you need to check if your network losing a lot of packets, and the memory/CPU usage on the remote system. If you are seeing high cpu you could try playing with what cipher spec you are using. Otherwise you'll need more/better cpu/memory/netowrking.

All of this said the better solution is something like nomachine, X2GO, or vnc.

  • This answer is not helpful for a post that is 8 years old.
    – number9
    Commented May 25, 2022 at 13:57
  • You are responding to an old post, but with no real new information. The other answers allude to your notes on it being "slow", and in fact point to latency. Please revise or remove.
    – number9
    Commented May 25, 2022 at 13:58

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