display - 1 screen extended to 3 on a notebook with ATI Mobility Radeon HD 4670 - how?

07
2014-07
  • overdriven

    Not sure if a proper stackexchange forum, but couldn't find any more related.

    Is graphic card ATI Mobility Radeon HD 4670 able to handle 2 screens?
    If it does, what Multi-Display Adapters you reccommend?

    • Answers
  • Seasoned Advice (cooking)

    The electrical design of all graphic ports is pretty smart at detecting the 75 Ohm termination impedance of monitor signals. Once this is detected on boot , the external VGA is cloned until the desktop configuration is loaded. Initially it will be blank or disabled until you chose a (.) beside extend this monitor [2]. You can expect [2] but using the HDMI port in addition to get [3] may have restrictions to the overall desktop size of shared CPU/GPU memory space.

    If you disconnect the cable, the video adapter will sense the disconnect of 75 Ohms and then react by disabling the video signal and pushing all the icons and windows to the main screen. Isn't Ohm's Law wonderful?


    • Related Question

    hdmi - ATI graphics card to feed three monitors
  • Mircea Chirea

    Assuming the monitors can take any kind of port and signal (digital/analog, DVI/HTMI, VGA, DisplayPort) so as to keep this only video card related:

    I'm looking to get a three-monitor setup using a single ATI Radeon HD 5XXX card. If I understand correctly the ATI hardware, the DVI and HDMI ports share the same video feed (since they're exactly the same digital video signal). However, what about VGA and DisplayPort?

    For instance take this video card from Gigabyte:

    Gigabyte video card with DVI, DP and VGA ports

    It has DVI, VGA and DisplayPort connectors. Can it feed three monitors?

    If not, what card should I get that can feed three monitors? I think it would need to have two DVI and one DP. The monitors are 1920x1080 and two 1280x1024.

    Here is another image. This one has a DVI, VGA and HDMI:

    Asus video card with DVI, HDMI and VGA ports


    • Related Answers
  • Mircea Chirea

    Reading AMD's ATI Eyefinity Validated Dongles page I can confirm this:

    • A maximum of two VGA, DVI, HDMI or passive DisplayPort connections can be used.
    • Active DisplayPort is required for three or more connections.

    That means I can connector three monitors, two using the DVI/HDMI/VGA ports and the other using DisplayPort, either directly or via an active converter.