How can I improve the NX connection

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    Hi! I have NX server 5.3.12 with h.264 codec installed on CentoOS 7.3.

    When I use VPN and try to connect to my NX server thru thin inetchannel it’s really slow to respond.

    To improve respond I disable:

    1. Network-adaptive display quality

    2. Multi-pass display encoding

    3. Set less quality in display settings

    But its still very slow. And I can’t reed anything in my terminal. Pls give me some advice how to get good picture in terminal and get speed in connection. Thank you!



    if there is a very limited bandwidth, I wouldn’t touch the settings at point 1 and 2, but rather let NoMachine do its job at controlling congestion. In fact checking those boxes will limit the ability of congestion control algorythms to adapt to detected network conditions by adjusting image quality dinamically. Those settings won’t change the final quality, they only affect the progression and the speed how the target quality is reached.

    In your case, I think that the best option is to act on the Quality slider only to find the best balance between quality and responsiveness, assuming that the lack of responsiveness is only, or mostly, due to limited bandwidth. Maybe it’s worth checking the network latency too (round trip time), if you didn’t do already (VPN could play a role here). You can do that also from NoMachine user interface (‘Take the statistics’), or with the ‘ping’ command.

    A last note about Capture2.png: that blurriness around edges of coloured images is due to the chroma subsampling introduced by the encoder. NoMachine has algorithms to correct such color shift (, but those are enabled only for quality level 5 or above (from the middle of the Quality slider to the right).


    any suggestion?


    @Ve0 what do you mean? Fra already provided some suggestions in his reply, see above 😉


    @Britgirl and I already know about suggestions in Fra reply. It doesn’t work.


    Hi Ve0,

    did you try to verify the network bandwidth actually available, and latency as I suggested above?


    If you haven’t enough bandwidth, or the latency across the two points is too high, it’s impossible to use comfortably a remote display software like NoMachine. So the first thing is to determine how much bandwidth and latency you have. Even the VPN software may not work at its best, for whatever reason, but making some simple tests, like opening a TTY connection, outside NoMachine, to check the interactivity and latency through the VPN, and trying to download a big file to see the available bandwidth, should give you a clear idea of where the problem is.

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