#1195 high cpu usage on server side


up to 2.5.2 i can confirm that tightvnc use high cpu usage when client connects. this impact intel atom performance like a lot, it uses 1 core for 100% its resource.

switch to realvnc did the trick and now the cpu usage is below 5%, almost the same as windows rdp. :) haven't test the 2.6 version since already jump the wagon to realvnc though.


  • chrone

    chrone - 2012-11-05
    • priority: 5 --> 7
  • chrone

    chrone - 2012-11-05

    forgot to tell you the machines i tested:
    the server sides are running on both windows xp home edition and windows 7 pro 32-bit,
    and the client sides are running on both windows xp professional and windows 7 pro 32-bit and 64-bit.

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    Anonymous - 2013-01-23

    I am seeing the same thing using 2.6.4. If I let tightvnc set idle it pegs 1 CPU core. If I am using it, I get about 1/3 of a CPU or less usage.

    Last edit: Anonymous 2015-11-05
  • Konstantin Akimov

    • status: open --> open-accepted
  • Konstantin Akimov

    Thanks you for your report.

    You use default settings? You may say parameters server configuration:
    "Screen polling cycle" and "Use mirror driver if available".
    You have installed mirror driver?

    What encoding type are you using?

  • chrone

    chrone - 2013-01-24

    my screen polling cycle is 30 and i don't recall that mirror driver is installed when installing the tightvnc.

    i use default encoding, never played with the settings except for the polling interval and the administration passwords.

  • Konstantin Akimov

    Value "Screen polling cycle" 30 is too small. Please, increment it. Default value must be 1000. Try 200ms or 500ms.

  • chrone

    chrone - 2013-01-25

    oh i see, 1000ms is too slow compared to realvnc, setting it up to 30ms makes everything much snappy.

    i'll try later with your suggesstion, 200ms, 500ms, and 1000ms. will post it later if have time to switch back to tight vnc. :)

    thanks for the support though. :)

  • Konstantin Akimov

    Try using mirror driver: usually, this provide best response time, but does not require such a heavy load on the CPU.

  • Konstantin Akimov

    • status: open-accepted --> closed-accepted
  • Konstantin Akimov

    • status: closed-accepted --> closed-rejected

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