VNC latency

Discussion in 'Mac Programming' started by etaleb, Aug 5, 2014.

  1. etaleb macrumors member

    Apr 7, 2012

    This isn't exactly a programming question but I think you programmers would perhaps know the answer to this. At my job, I have to deal with a large number of computers (workstations & servers) by doing both RDP and VNC. For Windows, I stick with RDP but when going from Mac to Mac, my only option is the in-built VNC. I've used all flavors of the VNC client but never seem to get the low-latency that RDP protocol offers. There is always some sort of wait in milliseconds for a screen to refresh, especially when there are certain graphics on the remote machine (even basic graphics). This behavior is mostly seen on Wi-Fi but can also be seen on a wired connection. It may seem minor but given the nature of my work, it affects my productivity

    Hopefully someone can cast a technical light into why VNC is never able to catch up to RDP
  2. mfram macrumors 65816

    Jan 23, 2010
    San Diego, CA USA
    I'm not an expert in either of these protocols, but I have a couple guesses.

    VNC is a more open protocol. I think it was designed to be more generic so that it is a common protocol that can be used by different systems. Windows, Linux, Mac, etc. In that sense, it must take a more generic approach so I believe that causes problems by making the graphics more verbose and the event handling a little less efficient. Also, I believe VNC was probably created with the assumption it would be used on a LAN.

    RDP was developed by Microsoft. So they were able to optimize for their system. Both in terms of graphics and event handling. I'm guessing that's the big difference.

    I use thin-clients at work to connect to VMs on a server. That remote desktop protocol is even more optimized than RDP. I forget which vendor it is. It's not important. The point is if you in control of both sides then you can optimize. VNC was designed to be more open to be cross-platform compatible.
  3. ArtOfWarfare macrumors G3


    Nov 26, 2007
    Reduce the size of what you're streaming, either by reducing the number of colors or by reducing the resolution. I generally don't have a problem streaming... I forget the exact resolution... 1400x900? Something like that. + full color quality. Over wifi.
  4. etaleb thread starter macrumors member

    Apr 7, 2012
    you are probably using citrix ica or vmware view - both of which are even more efficient though microsoft with remoteFX has gotten close to them
  5. firewood macrumors 604

    Jul 29, 2003
    Silicon Valley
    VNC is built on top of the OS window system. It waits for the desktop to change, the sends it. Microsoft built RDP inside Windows, which means RDP can start sending shorter drawing commands and stuff before it's finished being displayed. Apple could do that with OS hooks under Quartz/CoreGraphics, but hasn't (except maybe for Apple TV AirPlay.)

    There seem to be 2 or 3 vendors of RDP servers for Mac OS X. Don 't know if they are any faster than the VNC Remote Desktop.
  6. chown33 macrumors 604

    Aug 9, 2009
    Sailing beyond the sunset
    Can you give some examples of VNC clients you've tried?

    For example, I've used "JollysFastVNC" before, and it was notably faster than Apple's builtin screen-sharing. That was well over a year ago, maybe more than two years, but I doubt the app has gotten worse.

    The app is on the Mac App Store, and the developer has a free trial (see MacUpdate).
  7. slayerizer macrumors 6502a

    Nov 9, 2012
    Teamviewer is free for personal use and works with both Mac & Windows. It can disable the remote wallpaper and do a lot more. If you create an account you can run the program as a service and connect to your machines from anywhere (phone,tablet, computer). I have my mom's computer binded to my account to I can help her as well!

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