Is one Thunderbolt port powerful enough to support two 4:3 ratio monitors?

Posted:
in Future Apple Hardware edited January 2014
Hello!



Although the new iMacs have been released, I thought I would post this question in future hardware.



I understand that thunderbolt is cable of incredible bandwidth, but do you think it would be possible for their to be some kind of cable splitter/adapter that would allow me to connect two 19" 4:3 monitors as my output from an iMac using only one Thunderbolt port?



It seems like one port should be enough to handle the connection with the Mac, so I am wondering if it might be possible to have a splitter. Perhaps it's not a question of bandwidth, but how Mac OS would interpret the outputs of two devices from one port.



Any thoughts?



(yes, I am hoping to not have to buy the higher end iMac with 2 Thunderbolt ports. I also am not a big fan of the glossy iMac screens and would like to use my existing dual monitors which are equal in height.)



Thanks so much!

Comments

  • Reply 1 of 4
    A simple "splitter" would not work.

    If there's not already, then soon, there will be "hubs" available... similar to those we use with USB and Firewire. Thunderbolt can also be "daisychained". In this case, the peripheral (monitor) needs to be designed to support daisychaining (evidenced by a second TB port on it.)
  • Reply 2 of 4
    Quote:
    Originally Posted by KingOfSomewhereHot View Post


    A simple "splitter" would not work.

    If there's not already, then soon, there will be "hubs" available... similar to those we use with USB and Firewire. Thunderbolt can also be "daisychained". In this case, the peripheral (monitor) needs to be designed to support daisychaining (evidenced by a second TB port on it.)





    KingOfSomewhereHot, you are very wise, and likely equally attractive. Thank you for your response!



    Hubs! Of course! I have two 4:3 19" Samsung monitors that work very well for me with my PowerPC PowerMac. I have been waiting patiently for an upgrade.



    I'd rather use both of my current screens and not the iMac's screen than use a mismatched pare. Hmm . . . come to think of it . . . I wonder if I would even be able to disable the iMac's monitor and just use an external two?



    At least I know that hubs would allow me to likely pick up some TB to VGA/DVI cables and connect my two monitors. Cool! Thanks again!
  • Reply 3 of 4
    karl kuehnkarl kuehn Posts: 756member
    Why would you want two 19" displays rather then one 27" display? To put numbers to this:



    Two 19" monitors probably display each have a resolution of 1280x1024 or 1440x900, so:



    1280 * 1024 * 2 (monitors) = 2,621,440 pixels

    or

    1440 * 900 * 2 = 2,592,000 pixels (widescreen)



    The 27" screen on the iMac displays 2560x1440 or 3,686,400 pixels.



    Unless your screens do something special, like wide color gamut, you are better off sticking with just the iMac, or using one or two screens as additional screens (1 on the 21.5", 2 on the 27").



    Oh, and since the screens for your PowerMac are probably either VGA or DVI connections (ADC is a form of DVI), they probably do not speak the packetized language of DisplayPort. You would need to have some device between the iMac and the displays that not only served as a ThunderBolt hub, but also could translate between DVI and DisplayPort. That would require not just the fairly simple wiring tricks in dongles, but rather a small processor to do the translation work. You can bet that if anyone ever makes such a beast it is going to be very expensive (more than the monitors are worth).



    If you read up on the ThunderBolt page on WikiPedia, the second paragraph mentions that this is a serial connection (e.g.: incompatible with DVI). However, the ThunderBolt connectors on the iMacs also support DVI, and even VGA connections with simple adapters, since the hardware in the iMac is capable of speaking those protocols. So the port can be any one of three ports: ThunderBolt, DVI, or VGA.
  • Reply 4 of 4
    Quote:
    Originally Posted by Karl Kuehn View Post


    Why would you want two 19" displays rather then one 27" display? To put numbers to this:



    Two 19" monitors probably display each have a resolution of 1280x1024 or 1440x900, so:



    1280 * 1024 * 2 (monitors) = 2,621,440 pixels

    or

    1440 * 900 * 2 = 2,592,000 pixels (widescreen)



    The 27" screen on the iMac displays 2560x1440 or 3,686,400 pixels.



    Unless your screens do something special, like wide color gamut, you are better off sticking with just the iMac, or using one or two screens as additional screens (1 on the 21.5", 2 on the 27").



    Oh, and since the screens for your PowerMac are probably either VGA or DVI connections (ADC is a form of DVI), they probably do not speak the packetized language of DisplayPort. You would need to have some device between the iMac and the displays that not only served as a ThunderBolt hub, but also could translate between DVI and DisplayPort. That would require not just the fairly simple wiring tricks in dongles, but rather a small processor to do the translation work. You can bet that if anyone ever makes such a beast it is going to be very expensive (more than the monitors are worth).



    If you read up on the ThunderBolt page on WikiPedia, the second paragraph mentions that this is a serial connection (e.g.: incompatible with DVI). However, the ThunderBolt connectors on the iMacs also support DVI, and even VGA connections with simple adapters, since the hardware in the iMac is capable of speaking those protocols. So the port can be any one of three ports: ThunderBolt, DVI, or VGA.



    Hi Karl,



    Thanks for your response!



    Yeah, I read that even the existing DVI to Mini DisplayPort Adaptors will work with the Thunderbolt port, so I should be okay with one of those and my monitors with Thunderbolt.



    I have actually been waiting on a refresh of the Mac Mini, but after looking at the new iMacs, I might just go for the low end one. I will probably wait to check out the Mini refresh first though.



    Anyway, that means that I would have a 21.5 wide screen, which would make one of my 19" screens taller than it. One would be glossy, one would be matte. I'm not even sure if screen resolutions will match up consistently for me to maximize my screen real estate. This makes me want to think ahead so if I can't deal with it, I can just opt to use my two existing monitors. Surely I have to have more screen with these two puppies than one 21.5".



    The 27" would be awesome, but my budget could only let me grab the low end iMac over the upcoming Mini.
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