# X11 Forwarding ssh very slow

## aleskandro

Hi I've a vps server with ssh configured to forward X11.

When I ssh -X  (or -Y) to it from my computer and try to start, for example, xterm, it is very slow to show window... After it shows xterm it is enough fast.

I monitored network traffic via nethogs and found that in the starting time there is much traffic at maximum client speed (30 kb/s): after start the application and traffic is much less.

How many things X server sends to vps to starting apps? Is there any way to speed up this start delay?

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## chithanh

X11 forwarding is not very bandwidth efficient.

You can try enabling compression with ssh -C which can help, but which also introduces a bit of latency.

Other than that, switch to a different protocol like vnc or nx.

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## Hu

As I understand it, the problem has less to do with bandwidth efficiency than to do with latency efficiency.  Although X11 programming resources emphasize that clients must minimize the number of round trips, many modern X11 clients assume that round trips are nearly free.  When the X server is hundreds of milliseconds away, each round trip is expensive.

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